Copyright 2013 Gravitas Publications, Inc.

Transcription

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3 Cover design: Opening page: Illustrations: David Keller David Keller Rebecca W. Keller, PhD Copyright 2013 Gravitas Publications, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. No part of this book may be used or reproduced in any manner whatsoever without written permission. Focus On Middle School Chemistry Student Textbook (softcover) ISBN Published by Gravitas Publications, Inc. Illustrations Chapter 9, 9.1: Art Today Chapter 10: All molecular coordinates were provided by the Brookhaven Protein Data Bank. Front cover: Water molecule showing both the bonding of two hydrogens to one oxygen and the van der Waals radii of the atoms Back cover, inside title page: L-alanine molecule one of the amino acids Special thanks to Susan Searles for copyediting and review of the manuscript. Also, I d like to thank the Keller kids (Kimberly, Chris, and Katy), the Chesebrough kids (Sam and Ben), and the Megill kids (Lorien, Lee, Joshua, and Joseph) for critical evaluation of the text. Finally, I d like to thank Lina and Lillian McEwan for valuable input.

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5 Contents CHAPTER 1: MATTER Introduction Atoms Periodic Table Summary 7 CHAPTER 2: MOLECULES From Atoms to Molecules Forming Bonds Types of Bonds Shared Electron Bonds Unshared Electron Bonds Bonding Rules Shapes of Molecules Summary 13 CHAPTER 3: CHEMICAL REACTIONS Introduction Combination Reaction Decomposition Reaction Displacement Reaction Exchange Reaction Spontaneous or Not? Evidences of Chemical Reactions Summary 19 CHAPTER 4: ACIDS, BASES, AND ph Introduction The ph Scale Properties of Acids and Bases Measuring ph Summary 24 CHAPTER 5: ACID-BASE NEUTRALIZATION Introduction Concentration Titration Plotting Data Plot of an Acid-Base Titration Summary 31

6 CHAPTER 6: MIXTURES Introduction Types of Mixtures Like Dissolves Like Soap Summary 39 CHAPTER 7: SEPARATING MIXTURES Introduction Filtration Evaporation Solids, Liquids, and Gases Chromatography Summary 44 CHAPTER 8: ENERGY MOLECULES Introduction Nutrients Carbohydrates Starches Cellulose Summary 50 CHAPTER 9: POLYMERS Introduction Polymer Uses Structure of Polymers Modifying Polymers Summary 55 CHAPTER 10: BIOLOGICAL POLYMERS: Proteins and DNA Introduction Proteins Proteins Are Amino Acid Polymers Proteins Form Special Shapes Protein Machines DNA DNA Structure Protein Machines on DNA Summary 64 Glossary Index 65

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8 2 FOCUS ON MIDDLE SCHOOL CHEMISTRY 1.1 Introduction What is chemistry? Have you ever wondered what the world and the objects in the world are made of? What is water exactly? Why do ice cubes float? What are our hair and skin made of? Why is a marble hard but a jellyfish soft? All of these questions, and others like them, begin the inquiry into that branch of science called chemistry. Chemistry is the study of matter which is a general term for what forms all living and nonliving things. Chemistry is concerned mainly with the properties of matter. All of the items we encounter on a daily basis are made of matter. Balloons are made of matter. Pancakes are made of matter. Baseballs are made of matter. Even our bodies are made of matter. But what makes up matter? 1.2 Atoms The fundamental building blocks of matter are atoms (a -tǝms). The word atom comes from the Greek word atomos, which means uncuttable. During the 5th century B.C. (B.C.E.), the Greek philosophers proposed the idea that there must be some smallest uncuttable units of matter. They called these units atoms.

9 CHAPTER 1: MATTER 3 Today we know that atoms are composed of even smaller particles called protons (prō -tänz), neutrons (nü -tränz ), and electrons (i-lek -tränz). Protons and neutrons are roughly equal in size, but electrons are very much smaller than both protons and neutrons. Protons, neutrons, and electrons are all much smaller than an atom. Protons and neutrons combine to form the central core or nucleus (nü klē ǝs) of an atom. The electrons occupy the space surrounding the nucleus. This space is sometimes called the electron cloud. The number of electrons in an atom always equals the number of protons. Notice that in the helium (hē -lē um) atom there are two protons and two electrons. Sometimes the number of protons also equals the number of neutrons, as with helium, but this is not always true. Most of the space of an atom is actually filled up by the electron cloud. The central core of an atom takes up only a very small part of the total space. On the other hand, almost all of the mass of the atom is in the protons and neutrons in the nucleus. The electrons weigh almost nothing compared to the nucleus, yet they take up all the space!

10 4 FOCUS ON MIDDLE SCHOOL CHEMISTRY 1.3 Periodic Table All of the atoms that make up the world are known. They are called chemical elements or just elements (e -lǝ-mǝnts). Early in the 19th century, a total of 55 chemical elements were known, and many more were being discovered. Their properties were very different from each other, and it was difficult to organize them. In 1867, Dmitri Mendeleev (dmē -trē men-dǝ-lā -ǝf) organized the elements into what is now called the periodic table of elements. In today s periodic table, the elements are arranged horizontally from left to right in order of increasing atomic number. The atomic number is the number of protons in the nucleus of each atom. For example, carbon has an atomic number of 6, which means it has 6 protons in its nucleus. Oxygen (äk -si-jǝn) has an atomic number of 8, which means it has 8 protons in its nucleus. All of the elements have a symbol. For example, hydrogen (hī -drǝ-jǝn) has the symbol H, and carbon has the symbol C. Notice that for these elements the symbol is the same as the first letter of the name. This is true for many elements because they have English names, like oxygen which has the symbol O. But some names come from other languages. The name for sodium (sō - dē-ǝm) comes from the Latin word natrium, so it has the symbol Na. Tungsten comes from the German word wolfram, so it has the symbol W. Other examples include gold, which has the symbol Au from the Latin word aurum, and lead (led), which has the symbol Pb from the Latin word plumbum.

11 CHAPTER 1: MATTER 5 As we just saw, the atomic number tells how many protons the atom contains. In an atom, the number of protons equals the number of electrons, so this number is also the number of electrons in an atom. For example, the smallest element is hydrogen. It has an atomic number of 1, which means it has only one proton. It also has only one electron, since the number of protons equals the number of electrons. Though atoms are very small, each one has a weight called the atomic weight. For most atoms the atomic weight is very close to the sum of the protons and neutrons in the nucleus. Both protons and neutrons have an atomic weight of 1. Electrons are so small that they are given almost no weight at all. The number of neutrons for an atom can be calculated by subtracting the number of protons from the atomic weight. For example, the atomic weight of hydrogen is , which is the number found below the name. To find the number of neutrons, the number of protons (1) is subtracted from the atomic weight ( or 1); 1-1 = 0. This means that hydrogen has no neutrons and only one proton in its nucleus. The largest naturally occurring element is uranium (yü rā nē ǝm). It has an atomic number of 92, which means it has 92 protons and 92 electrons. It has an atomic weight of To calculate the number of neutrons, the number of protons is subtracted from the atomic weight ( = 146), so uranium has 146 neutrons.

12 6 FOCUS ON MIDDLE SCHOOL CHEMISTRY The elements in the periodic table are arranged vertically according to their chemical properties. All of the elements in a single column undergo similar chemical reactions and have similar chemical properties. All of the elements in the far right-hand column are called the noble gases. They are similar to each other because they don t react with other atoms or molecules. The elements in the far left-hand column are called the alkali (al -kǝ-lī) metals. They are similar to each other because they react with lots of different atoms or molecules. The periodic table of elements organizes a lot of information about the elements and their chemical properties. This table helps chemists predict the behavior of the elements and how they might interact with each other. Before all of the naturally occurring elements were known, Mendeleev used the organization of his table to predict many of the properties of the missing elements. The success of his predictions and the organization of his chart led to its acceptance as a major scientific accomplishment.

13 CHAPTER 1: MATTER Summary Here are the most important points to remember from this chapter: All things, both living and nonliving, are made of atoms. Atoms are made of protons, neutrons, and electrons. In an atom, the number of protons equals the number of electrons. All atoms (elements) are found in the periodic table of elements. The elements are arranged in the periodic table in groups that are similar.

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15 CHAPTER 3: CHEMICAL REACTIONS Introduction What happens inside a battery? How does a car use gasoline to run? What happens to an egg when it s fried in a pan? All of these situations are examples of chemical reactions at work. Chemical reactions happen almost everywhere we look. They provide the energy that powers many things including cars, toys, plants, and animals. Our own bodies work by means of many complex chemical reactions. A chemical reaction occurs whenever bonds between atoms and molecules are created or destroyed. The following are four general types of chemical reactions: 1. Combination (käm-bǝ-nā -shǝn) reactions occur when two or more molecules combine with each other to make a new molecule. 2. Decomposition (dē-käm-pǝ-zi -shǝn) reactions occur when a molecule decomposes, or breaks apart, into two or more molecules. 3. Displacement (dis-plās -mǝnt) reactions occur when one atom kicks another atom out of a molecule. 4. Exchange (eks-chānj ) reactions occur when one atom trades places with another atom. 3.2 Combination Reaction In a combination reaction, two or more molecules combine to form a single product. The reaction of sodium and chlorine (klôr -ēn) to make sodium chloride, or table salt, is an example of a combination reaction. In this reaction two sodium atoms combine with one molecule of chlorine gas to make two molecules of sodium chloride.

16 16 FOCUS ON MIDDLE SCHOOL CHEMISTRY 3.3 Decomposition Reaction In a decomposition reaction, molecules of one type break apart or decompose to make two or more products. The breakup of water into hydrogen and oxygen gases is an example of a decomposition reaction. 3.4 Displacement Reaction A third general type of chemical reaction is the displacement reaction. In this reaction, one atom will remove another atom from a compound to form a new product. The formation of sodium hydroxide from two water molecules and two sodium atoms is an example of a displacement reaction. For each of the two water molecules, one sodium atom (shown as a blue ball labeled Na ) kicks one hydrogen atom (shown as a gray ball labeled H ) out of the water molecule. Then the sodium atom combines with the remaining oxygen atom and hydrogen atom (called a hydroxide [hī dräk sīd] ion) to make a new molecule called sodium hydroxide. Hydrogen gas is formed by the two hydrogen atoms that were kicked out of the two water molecules by the sodium atoms.

17 CHAPTER 3: CHEMICAL REACTIONS Exchange Reaction The fourth type of general chemical reaction is the exchange reaction. In this reaction, the atoms of one molecule trade places with the atoms of another molecule to form two new molecules. The reaction of hydrochloric acid (HCl) and sodium hydroxide (NaOH) is an example of an exchange reaction. The hydrogen atom in the HCl molecule trades places with the sodium atom in the NaOH molecule to make two new molecules, sodium chloride (table salt) and water. These are the basic types of simple chemical reactions. Some reactions that have many components are much more complicated than those outlined in this chapter, but most chemical reactions fall into one of these four categories. 3.6 Spontaneous or Not? Not all chemical reactions are spontaneous (spän-tā -nē-ǝs). Spontaneous means the reaction happens all by itself, just by mixing the chemicals. The exchange reaction of hydrochloric acid (HCl) and sodium hydroxide (NaOH) is a spontaneous reaction; however, not all chemical reactions are spontaneous. The decomposition reaction of water into hydrogen gas and oxygen gas is not a spontaneous reaction. It requires either high heat or an electric current. It s a good thing that not all reactions occur spontaneously. Imagine how difficult it would be to swim or sail a boat or even get a drink, if water spontaneously decomposed into hydrogen gas and oxygen gas!

18 18 FOCUS ON MIDDLE SCHOOL CHEMISTRY 3.7 Evidences of Chemical Reactions To determine whether or not a chemical reaction has occurred, chemists look for certain signs, or evidences, of a change. There are several signs that tell scientists when a chemical reaction has occurred. A chemist may look for bubbles being released when something gets added to something else. Bubbles indicate that a gas formed during the reaction. Or, if two solutions are mixed, the resulting new solution might change color. Sometimes when two solutions are mixed, a temperature change occurs, and the solution gets either hotter or colder. Finally, another indication that a chemical reaction has taken place is the formation of a precipitate (pri-si -pǝ-tāt), which can look like colored sand, mud, dust, or snow forming in a solution. A precipitate forms when the new molecules being made from the chemical reaction do not dissolve in the solution. These are some of the ways that chemists can tell when a chemical reaction has taken place.

19 CHAPTER 3: CHEMICAL REACTIONS Summary Here are the most important points to remember from this chapter: A chemical reaction occurs whenever bonds between atoms and molecules are created or destroyed. There are different kinds of chemical reactions. They are as follows: combination reactions where molecules join decomposition reactions where molecules break apart displacement reactions where atoms are removed from molecules exchange reactions where atoms of one molecule trade places with atoms of another molecule Not all chemical reactions occur spontaneously. Sometimes changes occur that indicate a chemical reaction has taken place. These changes include bubble formation, color changes, temperature changes, and the formation of precipitates (precipitation).

20 Laboratory Workbook Rebecca W. Keller, PhD

21 Cover design: David Keller Opening page: David Keller, Rebecca W. Keller, PhD Illustrations: Rebecca W. Keller, PhD Copyright 2013 Gravitas Publications, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. Focus On Middle School Chemistry Laboratory Workbook ISBN: Published by Gravitas Publications, Inc. Printed in the United States

22 Introduction iii Keeping a Laboratory Notebook A laboratory notebook is essential for the experimental scientist. In this type of notebook, the results of all the experiments are kept together along with comments and any additional information that is gathered. For this curriculum, you should use this workbook as your laboratory notebook and record your experimental observations and conclusions directly on its pages, just as a real scientist would. The experimental section for each chapter is pre-written. The exact format of a notebook may vary among scientists, but all experiments written in a laboratory notebook have certain essential parts. For each experiment, a descriptive but short Title is written at the top of the page along with the Date the experiment is performed. Below the title, an Objective and a Hypothesis are written. The objective is a short statement that tells something about why you are doing the experiment, and the hypothesis is the predicted outcome. Next, a Materials List is written. The materials should be gathered before the experiment is started. Following the Materials List is the Experiment. The sequence of steps and all the details for performing the experiment are written beforehand. Any changes made during the experiment should be written down. Include all information that might be of some importance. For example, if you are to measure 237 ml (1 cup) of water for an experiment, but you actually measured 296 ml (1 1/4 cup), this should be recorded. It is hard sometimes to predict the way in which even small variations in an experiment will affect the outcome, and it is easier to track a problem if all of the information is recorded. The next section is the Results section. Here you will record your experimental observations. It is extremely important that you be honest about what is observed. For example, if the experimental instructions say that a solution will turn yellow, but your solution turned blue, you must record blue. You may have done the experiment incorrectly, or you might have discovered a new and interesting result, but either way, it is very important that your observations be honestly recorded. Finally, the Conclusions should be written. Here you will explain what the observations may mean. You should try to write only valid conclusions. It is important to learn to think about what the data actually show and also what cannot be concluded from the experiment.

23 iv Focus On Middle School Chemistry Laboratory Workbook Laboratory Safety Most of these experiments use household items. However, some items, such as iodine, are extremely poisonous. Extra care should be taken while working with all chemicals in this series of experiments. The following are some general laboratory precautions that should be applied to the home laboratory: Never put things in your mouth without explicit instructions to do so. This means that food items should not be eaten unless tasting or eating is part of the experiment. Use safety glasses while working with glass objects or strong chemicals such as bleach. Wash hands before and after handling chemicals. Use adult supervision while working with iodine and while conducting any step requiring a stove.

24 Contents Experiment 1: What Is It Made Of? 1 Review 6 Experiment 2: Making Marshmallow Molecules 7 Review 12 Experiment 3: Identifying Chemical Reactions 13 Review 17 Experiment 4: Making an Acid-Base Indicator 18 Review 22 Experiment 5: Vinegar and Ammonia in the Balance: An Introduction to Titrations 23 Review 28 Experiment 6: Mix It Up! 29 Review 33 Experiment 7: Black Is Black? 34 Review 38 Experiment 8: Show Me the Starch! 39 Review 42 Experiment 9: Gooey Glue 43 Review 47 Experiment 10: Amylase Action 48 Review 51

25 Experiment 1: What Is It Made Of? 1 Experiment 1: What Is It Made Of? Date: Objective To become familiar with the periodic table of elements and investigate the composition of some common items Materials pen or pencil food labels periodic table of elements resources (books or online) such as: dictionary encyclopedia computer with internet access (optional) Experiment Using the periodic table of elements, answer the following questions: A. How many protons does aluminum have? How many electrons? B. What is the symbol for carbon? C. List all the elements that have chemical properties similar to helium. D. What is the atomic weight of nitrogen? How many neutrons does nitrogen have?

26 2 Focus On Middle School Chemistry Laboratory Workbook In the table on the next page, fill in the following information. ITEM Think of several different items and write them in the column labeled ITEM. These can be any item, like tires or cereal. Try to be specific. For example, instead of writing just cereal, write corn cereal or sweet, colored cereal. COMPOSITION In an encyclopedia, on the food label, or online, look up the composition of the items you have selected, and write this information in the column labeled COMPOSITION. Try to be as specific as possible when identifying the composition. For example, if your cereal contains vitamin C, write sodium ascorbate if that name is also listed. Try to identify any elements that are in the compounds you have listed. For example, vitamin C contains the element sodium. SOURCE Write the source next to the composition. Source means where you got your information; for example, food label or encyclopedia, or if you got the information online, list the name of the website.

27 Experiment 1: What Is It Made Of? 3 ITEM COMPOSITION SOURCE

28 4 Focus On Middle School Chemistry Laboratory Workbook Results Briefly describe what you discovered about the composition of the various items. For example: Kellogg s Sugar Smacks cereal contains vitamin C, which is called sodium ascorbate.

29 Experiment 1: What Is It Made Of? 5 Conclusions State your conclusions based on the information you collected. For example: Many cereals contain sodium in the form of salt and vitamin C.

30 6 Focus On Middle School Chemistry Laboratory Workbook Review Define the following terms: chemistry matter atoms (atomos) proton neutron electron nucleus electron cloud element atomic weight

31 Experiment 3: Identifying Chemical Reactions 13 Experiment 3: Identifying Chemical Reactions Date: Objective Hypothesis In this experiment we will try to identify a chemical reaction by observing the changes that occur when two solutions are added together. A chemical reaction can be identified by observing changes that occur in the course of the reaction. Materials baking soda lemon juice balsamic vinegar salt and water: ml salt dissolved in 120 ml water (1-2 tbsp. salt dissolved in 1/2 cup of water) egg whites milk several small jars measuring cups and spoons eye dropper Experiment Look at the chart in the Results section. Write down all of the substances (baking soda, lemon juice, balsamic vinegar, salt water, egg whites, and milk) horizontally with one item above each column. Now write the same list of items vertically down the left side of the grid, next to each row. There should be an item assigned to each column and to each row. In the white boxes of the chart on the next page, record what you observe when the item listed in the column is mixed with the item in the corresponding row.

32 14 Focus On Middle School Chemistry Laboratory Workbook Look especially for changes that indicate a chemical reaction has taken place. For example, look for bubbles, color change, or a precipitate. Ask your teacher for unknown solutions. When you mix them, try to determine whether a chemical reaction has taken place. Try to identify what the unknown solutions are. Results

33 Results for Unknown Solutions Description of each unknown solution: Experiment 3: Identifying Chemical Reactions 15 Results when the two are mixed: What might they be?

34 16 Focus On Middle School Chemistry Laboratory Workbook Conclusions

35 Experiment 3: Identifying Chemical Reactions 17 Review What are the four types of chemical reactions? Define the following terms: chemical reaction combination reaction decomposition reaction displacement reaction exchange reaction spontaneous List four signs that may be observed that indicate a chemical reaction has occurred.

36 Teacher s Manual Rebecca W. Keller, PhD

37 Cover design: David Keller Opening page: David Keller, Rebecca W. Keller, PhD Illustrations: Rebecca W. Keller, PhD Copyright 2013 Gravitas Publications, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. Focus On Middle School Chemistry Teacher s Manual ISBN Published by Gravitas Publications, Inc. Printed in United States

38 FOCUS ON MIDDLE SCHOOL CHEMISTRY TEACHER S MANUAL Introduction iii A Note From the Author This curriculum is designed to give students both solid science information and hands-on experimentation. The middle school material is geared toward fifth through eighth grades, but much of the information in the text is very different from what is taught at this grade level in other textbooks. I feel that students beginning with the fifth grade can grasp the concepts presented here. This is a real science text, so scientific terms are used throughout. It is not important at this time for students to master the terminology, but it is important that they be exposed to the real terms used to describe science. For students, each chapter has two parts: a reading part in the Focus On Middle School Chemistry Student Textbook and an experimental part in the Focus On Middle School Chemistry Laboratory Workbook. In this teacher s manual, an estimate is given for the time needed to complete each chapter. It is not important that both the reading portion and the experimental portion be concluded in a single sitting. It may be better to have students do these on two separate days, depending on the interest level of the child and the energy level of the teacher. Also, questions not addressed in the Teacher s Manual may arise, and extra time may be required to investigate these questions before proceeding with the experimental section. Each experiment is a real science experiment and not just a demonstration. They are designed to engage students in an actual scientific investigation. The experiments are simple but are written the way real scientists actually perform experiments in the laboratory. With this foundation, it is my hope that students will eventually begin to think of their own experiments and test their own ideas scientifically. Enjoy! Rebecca W. Keller, PhD

39 iv FOCUS ON MIDDLE SCHOOL CHEMISTRY TEACHER S MANUAL Introduction How To Use This Manual Each chapter in this Focus On Middle School Chemistry Teacher s Manual begins by providing additional information for the corresponding chapter in the student textbook. This supplementary material is helpful when questions arise while students are reading the text. It is not necessary for students to learn this additional material since most of it is beyond the scope of this level. However, the teacher may find the information helpful when answering questions. The second part of each chapter in the Teacher s Manual provides directions for the experiments in the Laboratory Workbook as well as answers to the questions asked in each experiment and review section. All of the experiments have been tested, but it is not unusual for an experiment to produce an unexpected outcome. Usually repeating an experiment helps both student and teacher see what might have occurred during the experimental process. Encourage the student to troubleshoot and investigate all possible outcomes. However, even repeating an experiment may not produce the expected outcome. Do not worry if an experiment produces a different result. Scientists don t always get the expected results when doing an experiment. The important thing is for students to learn about the scientific method and to make observations, think about what is taking place, and ask questions. Getting Started The experimentation process will be easiest if all the materials needed for the experiment are gathered together and made ready before beginning. It can be helpful to have a small shelf or cupboard or even a plastic bin dedicated to holding most of the necessary chemicals and equipment. The following Materials at a Glance chart lists all of the materials needed for each experiment. An additional chart lists the materials by type and quantity. A materials list is also provided at the beginning of each lesson.

40 FOCUS ON MIDDLE SCHOOL CHEMISTRY TEACHER S MANUAL Introduction v Materials at a Glance Experiment 1 Experiment 2 Experiment 3 Experiment 4 Experiment 5 pen labels from food products periodic table of elements (from Focus on Middle School Chemistry Textbook) books or online: dictionary encyclopedia computer with internet access (optional) small, colored marshmallows large marshmallows optional replacements for marshmallows: gumdrops or jelly beans toothpicks baking soda lemon juice balsamic vinegar salt (1-2 Tbsp. dissolved in 1/2 cup of water) egg whites milk several small jars measuring cups measuring spoons eye dropper (See next page for materials for optional activity) one head red cabbage distilled water ammonia vinegar soda pop milk mineral water large saucepan knife small jars coffee filters (white) eye dropper measuring cup measuring spoons marking pen scissors ruler red cabbage indicator (from Experiment 4) household ammonia vinegar large glass jar measuring spoons measuring cup Experiment 6 Experiment 7 Experiment 8 Experiment 9 Experiment 10 water ammonia vegetable oil rubbing alcohol melted butter vinegar small jars (7 or more) food coloring dish soap eye dropper measuring spoons measuring cup marking pen (See next page for materials for optional activity) ballpoint ink pens (various colors) black ballpoint ink pen rubbing alcohol coffee filters (white) several small jars cardboard shoe box tape measuring cup scissors ruler tincture of iodine (from Walgreen s or other pharmacy) raw food items: pasta, bread, celery, potato, banana, apple, etc. liquid laundry starch absorbent white paper eye dropper cookie sheet marking pen liquid laundry starch (or Borax) Elmer s white glue Elmer s blue glue (or another glue different from white glue) water 2 small jars marking pen Popsicle sticks for stirring measuring spoons tincture of iodine (from Walgreen s or other pharmacy) bread timer wax paper marking pen cup

41 vi FOCUS ON MIDDLE SCHOOL CHEMISTRY TEACHER S MANUAL Introduction Materials at a Glance By type with total quantities Equipment Materials (cont.) Food Items Just For Fun computer with internet access (optional) cookie sheet cup eye dropper jar, large glass jars, small, 7 or more measuring cups measuring spoons ruler saucepan, large scissors timer Materials Focus On Middle School Chemistry Laboratory Workbook ammonia, 200 ml [1 cup] box, cardboard shoe box or similar size coffee filters,white (several) dictionary (book or online) dish soap, 45 ml [3 Tbsp.] encyclopedia (book or online) labels from food products glue, Elmer s blue (or another glue different from white glue), 60 ml [1/4 cup] glue, Elmer s white, 60 ml [1/4 cup] iodine, tincture of (from Walgreen s or other pharmacy), several droppers laundry starch, liquid (or 30 ml [2 Tbsp] each of borax and cornstarch) paper paper, absorbent white paper, wax pen pens, inexpensive ballpoint (1 each: black, blue, red, green, etc.) or multicolored pen with 7-8 colors pen, marking pencil periodic table of elements (from Focus On Middle School Chemistry Student Textbook) rubbing alcohol, 135 ml [1/2 cup] sticks, Popsicle, several tape toothpicks, 1 pkg baking soda, ml [1-2 Tbsp.] bread butter, 75 ml [1/3 cup] cabbage, red (one head) egg whites (1 or 2) food coloring gumdrops (optional replacement for marshmallows), 1 pkg jelly beans (optional replacement for marshmallows), 1 pkg lemon juice, ml [1-2 Tbsp.] marshmallows, large, 1 pkg marshmallows, small, colored, 1 pkg milk, 420 ml [1 3/4 cup] raw foods (1 or 2 pieces each): pasta bread, 2 slices celery potato banana other fruits salt, ml [1-2 Tbsp.] soda pop, 15 ml [1 Tbsp.] vegetable oil, 90 ml [3/8 cup] vinegar, 345 ml [1.5 c.] vinegar, balsamic, ml [1-2 Tbsp.] optional, but recommended water, distilled, 1.1 liter [4.5 cups] water, mineral, 15 ml [1 Tbsp] water, tap Optional Activities Exper. 3: Peanut Brittle 360 ml (1 1/2 cups) sugar 240 ml (1 cup) white corn syrup 120 ml (1/2 cup) water 360 ml (1 1/2 cups) raw peanuts 5 ml (1 teaspoon) baking soda sauce pan buttered pan Exper. 6: Easy Chocolate Cake 710 ml (3 cups) flour 470 ml (2 cups) sugar 120 ml (1/2 cup) cocoa 5 ml (1 tsp) salt 175 ml (3/4 cup) shortening 2 eggs 240 ml (1 cup) buttermilk 240 ml (1 cup) boiling water 10 ml (2 teaspoons) baking soda saucepan mixing bowl mixing spoon or mixer 3 layer-cake pans

42 FOCUS ON MIDDLE SCHOOL CHEMISTRY TEACHER S MANUAL Introduction vii Laboratory Safety Most of these experiments use household items. However, some substances, such as iodine, are extremely poisonous. Extra care should be taken while working with all chemicals in this series of experiments. The following are some general laboratory precautions that should be applied to the home laboratory: Never allow students to put things in their mouth unless the experiment instructs them to do so. This means that food items should not be eaten unless tasting or eating is part of the experiment. Have students use safety glasses while working with glass objects or strong chemicals such as bleach. Have students wash their hands after handling all chemicals. Provide adult supervision while students are working with iodine or glassware and while conducting any step requiring a stove.

43 Contents Chapter 1: Matter 1 Experiment 1: What Is It Made Of? 6 Review of Terms 9 Chapter 2: Molecules 10 Experiment 2: Making Marshmallow Molecules 14 Review of Terms 19 Chapter 3: Chemical Reactions 20 Experiment 3: Identifying Chemical Reactions 24 Review of Terms 27 Chapter 4: Acids, Bases, and ph 28 Experiment 4: Making an Acid-Base Indicator 32 Review of Terms 35 Chapter 5: Acid-Base Neutralization 36 Experiment 5: Vinegar and Ammonia in the Balance: An Introduction to Titrations 40 Review of Terms 44 Chapter 6: Mixtures 45 Experiment 6: Mix It Up! 49 Review of Terms 53 Chapter 7: Separating Mixtures 54 Experiment 7: Black Is Black? 58 Review of Terms 62 Chapter 8: Energy Molecules 63 Experiment 8: Show Me the Starch! 67 Review of Terms 70 Chapter 9: Polymers 71 Experiment 9: Gooey Glue 75 Review of Terms 79 Chapter 10: Biological Polymers: Proteins and DNA 80 Experiment 10: Amylase Action 85 Review of Terms 87

44 Chapter 1: Matter Overall Objectives Introduction Atoms Periodic Table Summary 5 Experiment 1: What Is It Made Of? 6 Conclusions 8 Review 9 Time Required Text reading Experimental Materials 30 minutes 1 hour pen or pencil labels from food products periodic table of elements (from Focus On Middle School Chemistry Student Textbook) resources (books or online) such as: dictionary encyclopedia computer with internet access (optional)

45 2 FOCUS ON MIDDLE SCHOOL CHEMISTRY Teacher s Manual Overall Objectives This chapter introduces the concept that all things, living and nonliving, are made of the same fundamental components called atoms. It is important to help students understand that although the world is full of a large number of both living and nonliving things, there is only a limited number of atoms, or elements, that make up all things. The variety observed in all things is a result of the vast number of ways that atoms can be combined with one another. For example, sodium (Na) is combined with chlorine (Cl) to make sodium chloride (NaCl) which is table salt. However, if you add an oxygen atom (O) to make sodium hypochlorite, NaOCl, you get bleach. 1.1 Introduction Matter is a general term for the substance of which all things are composed. Chemistry is that area of science mainly concerned with the ways in which atoms combine to form chemical bonds. There are several different subdisciplines within chemistry: Physical chemistry is concerned with the fundamental physics of atoms. Biochemistry is concerned with matter that makes up living things. Organic chemistry is concerned with the chemistry of carbon containing compounds. Analytical chemistry deals with analyzing the composition of matter. Inorganic chemistry is concerned mostly with non-carbon compounds. 1.2 Atoms Students will be introduced to the following terms: Atoms Protons Neutrons Electrons Atoms, protons, neutrons and electrons are more specific terms for matter. Atoms are very small and cannot be seen by the naked eye. If an atom were the size of a tennis ball, the average man (6 ft. tall) would stand one million kilometers high almost the distance from here to the Sun.

46 CHAPTER 1 Matter 3 Protons and neutrons are roughly equal in size, and both have an atomic mass of 1 amu (atomic mass unit). A proton carries a positive charge, and a neutron carries no charge it is neutral. By comparison, the electron is 1/1836 of the mass of a proton. The electron carries a negative charge that is equal in magnitude to the charge on a proton. For neutral atoms, the number of electrons equals the number of protons. The number of neutrons does not always equal the number of protons or electrons in neutral atoms. The nucleus contains the protons and neutrons and is much smaller than the full atom. Most of the volume of an atom is occupied by the electrons. The space occupied by the electrons surrounds the proton-neutron core and is called an orbital or electron cloud. Orbitals can have a variety of shapes, and the different shapes of electron clouds are very important for understanding how atoms combine with each other. (This will be covered in the textbook for the next level.) 1.3 Periodic Table The periodic table of elements is a large chart that organizes and categorizes all of the elements according to their chemical properties. The periodic table illustrates the general law of periodicity among all of the elements. This means that certain chemical properties of the atoms repeat. For example, fluorine (F) undergoes chemical reactions similar to those of chlorine (Cl), bromine (Br), iodine (I), and astatine (At). All of these similar elements are arranged in a single column of the periodic table. Grouping the elements according to their chemical properties gives rise to the periods which are the horizontal rows. There are three short periods of 2, 8, and 8 elements: hydrogen -> helium [period of 2 elements] lithium -> neon [period of 8 elements] sodium -> argon [period of 8 elements] and then three longer periods of 18, 18, and 32: potassium -> krypton [period of 18 elements] rubidium ->xenon [period of 18 elements] cesium ->radon [period of 32 elements] The final period is predicted to contain 32 elements, but notice that the last elements are as yet undiscovered. The last naturally occurring element is uranium with 92 protons. The elements after uranium are artificially made.

47 4 FOCUS ON MIDDLE SCHOOL CHEMISTRY Teacher s Manual The symbols of the elements are not always the same as the first letter or two of the English name since some elements were named in other languages. Examples are given in the student textbook. The following details of the periodic table are explained briefly in the textbook. The number in the upper left-hand corner of each element square is the atomic number. This number tells how many protons the atom contains. The atomic number is not always in the upper-left-hand corner of the block representing the element it can be in the middle or on the right. The number below the name of the element is the atomic weight. The atomic weight is the sum of the weight of the protons, neutrons, and electrons. Because the electrons have essentially no mass, the atomic weight can be considered to be the sum of just the weight of the protons and neutrons. Because protons and neutrons are essentially 1 atomic mass unit each, the number of neutrons can be determined by subtracting the atomic number from the atomic weight. Examples: Hydrogen has an atomic number of 1. This means that hydrogen has one proton. Also, hydrogen has an atomic weight close to one, which means that all of the weight is due to the single proton. There are no neutrons. Another example is uranium: number of protons: 92 atomic weight: 238 number of neutrons: 238 minus 92 = 146 NOTE: Although the atomic weight is actually , it is rounded to 238 to calculate the number of neutrons. The elements are organized vertically in the periodic table according to similar chemical properties. The elements on the far right of the periodic table are the noble gases. In general, the noble gases do not react with other elements. It is possible to get some of the noble gases to react, but it is very difficult. The noble gases are always found in nature as single atoms and not in pairs like other gases such as oxygen and nitrogen. The elements on the far left are called the alkali metals. These elements are very reactive. Lithium (Li), sodium (Na), and potassium (K) react very violently with water. They also form salts with the halogens, which form the column to the left of the noble gases. Some common salts include sodium chloride (NaCl), lithium chloride (LiCl), and potassium chloride (KCl). Sodium chloride (NaCl) is common table salt. Potassium chloride (KCl) is a table salt alternative that is used by many people with high blood pressure.

48 CHAPTER 1 Matter 5 There are other trends or properties that are illustrated in the periodic table, such as atomic size and electronegativity, and these will be introduced later. The most important points to emphasize about the periodic table are the following: All of the elements that make up all things, living and nonliving, are in the periodic table. The periodic table illustrates an underlying order or periodicity among all of the elements. Mendeleev discovered the overall order of elements through scientific investigation and assembled the first periodic table. 1.4 Summary Discuss with the students the main points of this chapter. Point out that everything we can touch is made of atoms. Have the students name several different items and discuss how these items are all made of atoms. Review that atoms are made of smaller particles called protons, neutrons, and electrons. Protons and neutrons form the atomic core, or nucleus, and electrons are found in the electron cloud surrounding the nucleus. Review that the number of protons equals the number of electrons in an atom. This is true for neutral atoms. It is possible to remove an electron from an atom or add an electron to an atom. The atom is then called an ion and has a positive or negative charge. (This will be discussed in the textbook for the next level.) All of the elements known are found in the periodic table of elements. New elements can be made artificially, but all naturally occurring elements are already known. Review that in the periodic table all of the elements are in groups that are similar. For example, the noble gases behave similarly and are in the same column.

49 6 FOCUS ON MIDDLE SCHOOL CHEMISTRY Teacher s Manual The goals of this experiment are to help students begin to investigate the things in their world and to have them start to examine what those things are made of. There are many possible answers for this experiment. By using basic resources such as the dictionary or encyclopedia, students may not be able to find the elemental composition of all the items they think of. Some examples of answers are the following: Things made of metals: soda cans and aluminum foil - aluminum silverware (steel) - iron, nickel, silver coins - copper, nickel jewelry - gold, silver Things we eat: salt - sodium and chlorine sugar - carbon, oxygen, hydrogen water - hydrogen and oxygen bread (carbohydrates) - carbon, oxygen, hydrogen, and other proteins and things Also, students can select food items with labels, such as cake mixes, cereal, noodles, and vitamins (with vitamins the label is very detailed so students can also find out how much of something is in the vitamin). Students DO NOT need to find every component for each item. To say that cake mix contains salt, flour, and sugar is enough. Let the students go as far as they want to with a particular item. Also, it is not necessary to look up components for each item the students think of. Pick a few and go from there. Experiment 1: What Is It Made Of? Date: Objective To become familiar with the periodic table of elements and investigate the composition of some common items Materials pen or pencil food labels periodic table of elements resources (books or online) such as: dictionary encyclopedia computer with internet access (optional) Experiment Using the periodic table of elements, answer the following questions: A. How many protons does aluminum have? 13 How many electrons? 13 B. What is the symbol for carbon? C C. List all the elements that have chemical properties similar to helium. The elements that have chemical properties that are similar to helium are neon, argon, krypton, xenon, and radon. D. What is the atomic weight of nitrogen? How many neutrons does nitrogen have? 7 neutrons In the table on the next page, fill in the following information. ITEM Think of several different items and write them in the column labeled ITEM. These can be any item, like tires or cereal. Try to be specific. For example, instead of writing just cereal, write corn cereal or sweet, colored cereal. COMPOSITION In an encyclopedia, on the food label, or online, look up the composition of the items you have selected, and write this information in the column labeled COMPOSITION. Try to be as specific as possible when identifying the composition. For example, if your cereal contains vitamin C, write sodium ascorbate if that name is also listed. Try to identify any elements that are in the compounds you have listed. For example, vitamin C contains the element sodium. SOURCE Write the source next to the composition. Source means where you got your information; for example, food label or encyclopedia, or if you got the information online, list the name of the website.

50 CHAPTER 1 Matter 7 (Answers may vary.) ITEM COMPOSITION SOURCE 1. graham crackers sodium bicarbonate (sodium) food label 2. graham crackers salt (sodium, chlorine) food label, dictionarypage car tires rubber (carbon and hydrogen) Wikipedia (or 4. EXPERIMENT A-D Aluminum (Al) has 13 protons. This means aluminum has 13 electrons as well. 13 Al Aluminum The symbol for carbon is C C Carbon The elements that have the same chemical properties as helium are in the same column in the periodic table. 2 He Helium 910 Ne F Neon 18 Ar Argon 36 Kr Krypton 54 Xe Xenon 86 Rn Radon The atomic weight of nitrogen is To calculate the number of neutrons, subtract the number of protons (7) from the atomic weight = 7. Nitrogen has 7 neutrons. It has the same number of 7 neutrons as it N has protons. Nitrogen

51 8 FOCUS ON MIDDLE SCHOOL CHEMISTRY Teacher s Manual Help the students write accurate statements about the data they have collected. Some examples are given. Next, help the students think specifically about what their data show. This is an important critical thinking step that will help them evaluate future experiments. Try to help them write concluding statements that are valid. Encourage them to avoid stating opinions or any conclusions that cannot be drawn strictly from their data. For example, it may be true that all cereals contain salt. However, this particular investigation cannot confirm or deny that conclusion. The most that can be stated from this investigation is Brand X contains salt and Brand Y contains salt, but any further statement is conjecture. Help them formulate their conclusions using the words some, all, many, and none. Point out that the statement, All cereals contain salt, is not valid, but based on this investigation, it is valid to say, Some cereals contain salt. Again, there are numerous possible answers. One student may list sugar as a component in soup, and another may list salt, and both answers could be correct. The true test is whether the statements about the data are valid or not valid. Results (Answers may vary.) Briefly describe what you discovered about the composition of the various items. For example: Kellogg s Sugar Smacks TM cereal contains vitamin C, which is called sodium ascorbate. Table salt is made of sodium and chlorine. Iodized table salt contains sodium, chlorine, and iodine. Chocolate cake mix contains sugar. Sugar has oxygen, hydrogen, and carbon in it. Conclusions (Answers may vary.) State your conclusions based on the information you collected. For example: Many cereals contain sodium as part of salt and vitamin C. Some peanut butter contains sugar. Rubber contains carbon and hydrogen. Also, try to show students where broad statements can be made validly. For example, All recent U.S. pennies contain copper is probably a valid statement even though we haven t checked every U.S. penny. This may seem fairly subtle, but the main point is to help them understand the kinds of valid conclusions science can offer based on scientific investigation.

52 CHAPTER 1 Matter 9 Review Define the following terms: (Answers may vary.) chemistry a branch of science concerned with the properties of matter matter a general term for what makes up all things atoms (atomos) the fundamental building blocks of matter. Atomos is a Greek word that means uncuttable proton a small particle found inside atoms neutron another small particle found inside atoms electron nucleus a particle found in an atom that is very much smaller than both protons and neutrons the central portion of an atom that consists of only the protons and neutrons electron cloud the space occupied by the electrons surrounding the nucleus element another name for any of the distinct atoms in the periodic table atomic weight the total weight of an atom; the weight of the protons and neutrons combined

53 Chapter 3: Chemical Reactions Overall Objectives Introduction Combination Reaction Decomposition Reaction Displacement Reaction Exchange Reaction Spontaneous or Not? Evidences of Chemical Reactions Summary 23 Experiment 3: Identifying Chemical Reactions 24 Conclusions 26 Review 27 Time Required Text reading Experimental Materials baking soda lemon juice balsamic vinegar salt egg whites milk 1 hour 1 hour water several small jars eye dropper measuring cup measuring spoons Just For Fun Peanut Brittle 360 ml (1 1/2 cups) sugar 240 ml (1 cup) white corn syrup 120 ml (1/2 cup) water 360 ml (1 1/2 cups) raw peanuts 5 ml (1 teaspoon) baking soda sauce pan buttered pan

54 CHAPTER 3 Chemical Reactions 21 Overall Objectives In this chapter students will begin to learn how atoms and molecules react to form and break chemical bonds. It is not important for the students to memorize the names of the reactions. Help them understand that in chemical reactions the atoms are rearranged. Electrons can be swapped back and forth between atoms, but the protons and neutrons remain in their original nucleus. 3.1 Introduction Point out to the students that chemical reactions occur everywhere. For example: Stomach acid helps to digest our food. When hair is straightened or permed, sulfur bonds are broken and reformed. Cars are powered by the combustion (chemical reaction) of gasoline with oxygen from the air. When iron is left outside it reacts with oxygen and rust forms. Four main divisions of chemical reactions are given. These are called combination reactions, decomposition reactions, displacement reactions, and exchange reactions. Most chemical reactions fall into these categories or are combinations of these categories. 3.2 Combination Reaction In a combination reaction, two or more molecules combine to form a single product. The example shown is the formation of sodium chloride (table salt) by combining sodium metal and chlorine gas. NOTE: In the reaction between sodium metal and chlorine gas, the chlorine gas is a dimer (two atoms of chlorine). The bond between the chlorine atoms is broken before the formation of sodium chloride, so there is an additional step that is not shown. 3.3 Decomposition Reaction In a decomposition reaction, molecules decompose or break down to form other molecules. Note that two molecules of water decompose into one molecule of oxygen gas and two molecules of hydrogen gas. This is called a balanced reaction, because the number of H and O atoms is the same before and after the reaction only the bonds change.

55 22 FOCUS ON MIDDLE SCHOOL CHEMISTRY Teacher s Manual 3.4 Displacement Reaction A displacement reaction is slightly harder to visualize than the other two reactions because bonds are breaking and reforming at the same time. In the reaction of water with sodium metal, the sodium atoms displace a hydrogen atom on each of the water molecules. The two free hydrogens then combine to make hydrogen gas (H 2 ). Note that this reaction is balanced because two water molecules react with two sodium atoms giving two molecules of sodium hydroxide (NaOH) and one molecule of hydrogen gas; thus, the same number and kind of atoms are present before and after the reaction. 3.5 Exchange Reaction In an exchange reaction, the atoms trade places. The example shown is the reaction of hydrochloric acid (HCl) and sodium hydroxide (NaOH). Again, bonds are both breaking and forming in this reaction. This particular exchange reaction is also an acid-base reaction and will be covered in more detail in subsequent chapters. Hydrochloric acid is a very strong acid and very harmful if swallowed. Sodium hydroxide is a very strong base and also very harmful if swallowed. Both of these will also cause burns on skin. However, when they are added together and react, they make table salt (which we eat) and water. If concentrated reagents (chemical substances) are used, the reaction is quite violent and will produce a large amount of heat. 3.6 Spontaneous or Not? Not all reactions occur spontaneously. Some reactions, like the decomposition of water, require energy input before the reaction will proceed. The reasons why one reaction is spontaneous and another is not are beyond the scope of this level. The key concepts are enthalpy and entropy. These are described in a branch of chemistry called chemical thermodynamics. 3.7 Evidences of Chemical Reactions There are several indicators that tell scientists when a chemical reaction has taken place. These include bubbles, color change, heat exchange, and precipitation. Sometimes more than one of these can occur at the same time. For example, both bubbles and heat can be given off together. Sometimes none of them occur, and more subtle methods must be used to detect the reaction. Bubbles form when one of the molecules produced is a gas. Color changes may indicate a variety of end products. Compounds that contain metals, like copper (Cu), often display color. Blood, for example,

56 CHAPTER 3 Chemical Reactions 23 contains iron (Fe). When blood is combined with oxygen, it is bright red; however, without oxygen it is a darker red. A solution can either give off heat (exothermic reaction) or take in heat (endothermic reaction). Most exothermic reactions are spontaneous. Precipitations occur when one or more products of the reaction are no longer soluble in the solution. 3.8 Summary Discuss with the students the following main points of this chapter: Molecules and atoms react with each other to form new molecules. There are four basic types of chemical reactions, and these can combine to make more complex reactions. Not all reactions occur spontaneously. Some chemical reactions can be observed.

57 24 FOCUS ON MIDDLE SCHOOL CHEMISTRY Teacher s Manual In this experiment the students will examine chemical reactions and try to identify when they occur. Balsamic vinegar is recommended because the reaction when it is mixed with baking soda will be more dramatic, but other kinds of vinegar may be used. Have the students put a small amount of each substance listed into its own jar, and then have them examine the contents of each jar, taking note of the properties of each substance. Have them record the color, texture, and odor next to each item on the materials list wherever possible. For example: Baking Soda: white powder, no odor Balsamic Vinegar: dark liquid, sour odor Although most of the items are food items, do not allow the students to taste them since tasting is not part of this experiment. A variety of food items in addition to those on the materials list may be used. Bleach and ammonia cause good chemical reactions, but they can give off strong odors and so neither of these chemicals is recommended. Experiment 3: Identifying Chemical Reactions Date: Objective Hypothesis Materials In this experiment we will try to identify a chemical reaction by observing the changes that occur when two solutions are added together. A chemical reaction can be identified by observing changes that occur in the course of the reaction. baking soda lemon juice balsamic vinegar salt and water: ml salt dissolved in 120 ml water (1-2 tbsp. salt dissolved in 1/2 cup of water) egg whites milk several small jars measuring cups and spoons eye dropper Experiment Look at the chart in the Results section. Write down all of the substances (baking soda, lemon juice, balsamic vinegar, salt water, egg whites, and milk) horizontally with one item above each column. Now write the same list of items vertically down the left side of the grid, next to each row. There should be an item assigned to each column and to each row. In the white boxes of the chart on the next page, record what you observe when the item listed in the column is mixed with the item in the corresponding row.

58 CHAPTER 3 Chemical Reactions 25 Look especially for changes that indicate a chemical reaction has taken place. For example, look for bubbles, color change, or a precipitate. Ask your teacher for unknown solutions. When you mix them, try to determine whether a chemical reaction has taken place. Try to identify what the unknown solutions are. Results milk milk lemon juice REACT precipitate salt water baking soda balsamic vinegar NO NO REACT precipitate egg whites NO Have the students write the reagents (chemicals used in chemical reactions) on the top and side of the grid provided. Have them mix some of each of two substances together in a clean jar and observe the results. It might be interesting to the students to check the order of addition add lemon juice to baking soda, then add baking soda to lemon juice to see if a difference can be observed (the order of addition should not matter). This is optional. lemon juice NO REACT bubbles NO REACT precipitate Have the students record their observations in the appropriate box for each reaction. salt water NO NO NO baking soda REACT bubbles NO balsamic vinegar REACT precipitate egg whites

59 26 FOCUS ON MIDDLE SCHOOL CHEMISTRY Teacher s Manual Give the students two unknown solutions. These can either be two that will react or two that won t react. This part of the experiment can be done more than once. The students may want to give you unknowns to see if you can identify them. Explain to the students that much of the time scientists are trying to figure out how to identify unknowns. The students have observed all of the reactants both before and after a reaction. They now have the necessary knowledge to identify an unknown. Another option is to give the students only one unknown. Have them guess what it might be before performing any tests. Then have the students test this unknown with each of the other reactants. Have them prove the identity of the unknown with the chemical reactions they have already observed. Have the students write valid conclusions. Help them state conclusions that reflect only the data found in this experiment. For example, Salt water does not react with anything is not a valid conclusion because we haven t tested everything. However, Salt water does not react with any of the items we tested is valid. Results for Unknown Solutions Description of each unknown solution: Results when the two are mixed: What might they be? Conclusions

60 CHAPTER 3 Chemical Reactions 27 Review (Answers may vary.) What are the four types of chemical reactions? decomposition reaction combination reaction displacement reaction exchange reaction Define the following terms: chemical reaction a process in which chemical bonds are broken or created between atoms and molecules combination reaction a reaction in which two molecules combine to form a single product decomposition reaction a reaction in which a molecule breaks apart to make two or more new molecules displacement reaction a reaction in which one atom removes another atom from a molecule Just For Fun Watch baking soda decompose and give off carbon dioxide gas while peanut brittle is being made. Peanut Brittle 360 ml (1 1/2 cups) sugar 240 ml (1 cup) white corn syrup 120 ml (1/2 cup) water 360 ml (1 1/2 cups) raw peanuts 5 ml (1 teaspoon) baking soda buttered pan Boil sugar, water, and syrup in a sauce pan over medium heat until the mixture turns a little brown. Add 360 ml (1 1/2 cups) raw peanuts Stir until golden brown. Don t overbrown. Add 5 ml (1 teaspoon) baking soda. Spread on buttered pan. exchange reaction a reaction in which one atom trades places with another atom in a different molecule spontaneous term describing when a reaction happens all by itself List four signs that may be observed that indicate a chemical reaction has occurred. bubbles forming color change temperature change precipitate formation

61 Middle School Lesson Plan Focus On Middle School Chemistry Rebecca W. Keller, PhD

62 Copyright 2014 Gravitas Publications, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. No part of this book may be used or reproduced in any manner whatsoever without written permission. Focus On Middle School Chemistry Lesson Plan Published by Gravitas Publications, Inc.

63 FOCUS ON MIDDLE SCHOOL CHEMISTRY LESSON PLAN Overview Teaching Real Science-4-Kids is as easy as Introduce content. 2. Perform an experiment. 3. Make connections. RS4K comes in easy-to-use modules that focus on a particular subject. Each subject module is designed to introduce your child to one of the foundational building blocks of science. Once your child has been introduced to these foundational subjects, he or she can build their science education from the ground up, understanding, mastering, and quickly learning new science information. The lesson plan This is a weekly lesson plan that will walk you through the middle school curriculum. There are 20 weeks of instruction for each subject module. You can teach the 20 weeks in one semester or one year depending on the age of your child. You decide how fast or slow to go with your child. If you are not sure about the pace, start slowly. It is better that your child learns fewer facts with more understanding than be overwhelmed by too much information. You also don t want to slow down an advanced learner. Here is a suggested guideline. Age 10-11: a subject module (20 weeks) in one year. Age 12-13: a subject module in one semester, combining two weeks of the Lesson Plan into one week of study. Each week is divided into three sections: content, experiment, and connections. 1. The content directs your child to learn the scientific facts in each subject. 2. The experiment allows your child to learn the steps of the scientific method. 3. Connections between science and language, history, philosophy, technology, and art are explored. NOTE: You will see chapter suggestions for the Chemistry KOGs. These are supplementary books that contain additional exercises to accompany each chapter of the textbook. If you own the Chemistry KOGs, this lesson plan will help you incorporate them into your teaching sessions. If not, you can still use the questions for open inquiry that you ll find in this lesson plan. You can modify the lesson plan as desired. There is no wrong way to teach science. Let your child explore, investigate, ask questions, examine, and observe everything they find interesting. The middle school age group is about bringing what they ve learned through experience and play into a formal scientific framework. In the Connections section of this Lesson Plan, there are many suggestions for additional study meant to engage you and your child in further explorations of science. These are open inquiry questions, so don t worry about trying to form right answers. Instead, these are suggestions for exploration, and exploration is the first step in learning. Every chapter has been aligned to the National Science Standards. (taken from the National Science Education Standards (1996) and the Framework for K-12 Science Education (2012) National Academies Press) Before you begin Open the teacher s manuals for the subject modules you have purchased. Look at the materials list for each subject module. Using a large container or bin, collect the nonperishable items from the lists. Organize the items in your container. This will help you be prepared for the experiments for each subject module. Look through this lesson plan which is easy to use and will help you organize your child s study. Need Help? We are here to help you! We have several support options available. If you like online communities, we have a Yahoo group that discusses experiments and ideas and even provides contacts for resale of RS4K curriculum. RS4K has a Facebook Fanpage where you can meet other RS4K users and ask questions directly to Dr. Keller. You can us and talk to our friendly staff who will be happy to help you with any questions you might have. office@gravitaspublications.com

64 2 Real Science-4-Kids Week 1 Chapter 1 Matter Content DAY 1 Have your child read Chapter 1. Allow open discussion and let your child ask questions. Explore questions using the internet or library. Experiment DAY 2 Have your child perform Experiment 1: What Is It Made Of? Use the additional information in the Teacher s Manual to guide the experiment. Connections DAY 3 Discuss the word atom. Have your child do an internet or library search and write the meaning of this word. Language KOG Chapter 1 DAY 4 DAY 5 Ask your child about their family history. How far back can they trace their family history? Explore the history of the atom in the same way. History KOG Chapter 1 Have your student look up the philosopher Democritus on the internet or at the library. Who was Democritus and what is his story? Philosophy KOG Chapter 1 Notes

65 FOCUS ON MIDDLE SCHOOL CHEMISTRY LESSON PLAN 3 Week 2 Chapter 1 Matter Experiment DAY 1 Discuss the conclusions from Experiment 1. Discuss and perform any modifications for the experiment. Connections DAY 2 Have a discussion about technology and atoms. What technologies do we have today because of the discovery of atoms? How has the discovery of atoms changed our everyday lives? Technology KOG Chapter 1 DAY 3 Have a discussion about art and atoms. How does science play a role in the arts? Art KOG Chapter 1 DAY 4 Have your student critically evaluate all they have learned this week. How does all of this information contribute to our understanding of atoms? Critical Thinking KOG Chapter 1 Review DAY 5 Exam. Have your student take the Chapter 1 quiz online or print it out. Standards Science as Inquiry - Content Standard A P Think critically and logically to make relationships between evidence and explanations. Physical Science - Content Standard B P Matter exists as different substances (made of atoms). Science and Technology - Content Standard E P Science and technology are reciprocal. Science helps drive technology and technology is essential to science. History and Nature of Science - Content Standard G P Science has a history, and people have been studying nature through science for a long time. From the National Science Education Standards (1996) and the Framework for K-12 Science Education (2012) National Academies Press.

66 4 Real Science-4-Kids Week 5 Chapter 3 Chemical Reactions Content DAY 1 Have your child read Chapter 3. Allow open discussion and let your child ask questions. Explore questions using the internet or library. Experiment DAY 2 Have your child perform Experiment 3: Identifying Chemical Reactions. Use the additional information in the Teacher s Manual to guide the experiment. Connections DAY 3 Discuss the word combine. Have your child do an internet or library search and write the meaning of this word. Language KOG Chapter 3 DAY 4 Ask your child about the history of chemical reactions. Who first discovered the chemical reaction? History KOG Chapter 3 DAY 5 Have your student look up the philosopher Heraclitus on the internet or at the library. Who was Heraclitus and what is his story? Philosophy KOG Chapter 3 Notes

67 FOCUS ON MIDDLE SCHOOL CHEMISTRY LESSON PLAN 5 Week 6 Chapter 3 Chemical Reactions Experiment DAY 1 Discuss the conclusions from Experiment 3. Discuss and perform any modifications for the experiment. Connections DAY 2 DAY 3 How does a water softener work? Look up water softeners on the internet and write a description of how they work. Discuss how technology has helped us purify water. Technology KOG Chapter 3 Discuss how balance, proportion and contrast combine with the elements of the visual arts. Art KOG Chapter 3 DAY 4 Have your student critically evaluate all they have learned this week. How does all of this information contribute to our understanding of chemical reactions? Critical Thinking KOG Chapter 3 Review DAY 5 Exam. Have your student take the Chapter 3 quiz online or print it out. Standards Science as Inquiry - Content Standard A P Science advances through legitimate skepticism. Asking questions and querying other scientists explanations is part of scientific inquiry. Physical Science - Content Standard B P Substances react chemically in characteristic ways with other substances to form new substances (compounds) with different characteristic properties. Science and Technology - Content Standard E P Science and technology are reciprocal. Science helps drive technology and technology is essential to science. History and Nature of Science - Content Standard G P Scientists formulate and test their explanations of nature using observation, experiments, and models. From the National Science Education Standards (1996) and the Framework for K-12 Science Education (2012) National Academies Press.

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69 Layout design: Karen Wood and Derrick Wood Original Content: Karen Wood Graphic design: David Keller Copyright 2013 Gravitas Publications, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. No part of this booklet may be used or reproduced in any manner whatsoever without written permission. Focus On Middle School Chemistry Study Folder and Answer Key ISBN # Published by Gravitas Publications, Inc. Special thanks to Marjie Bassler for copy editing and review of the manuscript. Also, a special thank you to all of the parents and students from Intelligent By Design Science Enrichment Education classes for their critical evaluation of the text. Finally, special thanks to Dr. Rebecca W. Keller for her encouragement to go forward with this project.

70 TABLE OF CONTENTS Focus On Middle School Chemistry Study Folder Directions Optional Study Folder Cover i ii Chapter 1 Matter 1 Chapter 2 Molecules 2 Chapter 3 Chemical Reactions 3 Note Flappers 3.5 and 3.7 3a Chapter 4 Acids, Bases, and ph 4 Note Flapper 4.3 4a Chapter 5 Acid-Base Neutralization 5 Note Flapper 5.3A 5a Chapter 6 Mixtures 6 Note Flapper 6.3 6a Chapter 7 Separating Mixtures 7 Note Flapper 7.5A 7a Chapter 8 Energy Molecules 8 Note Flappers 8.4B and 8.5 8a Chapter 9 Polymers 9 Chapter 10 Biological Polymers: Proteins Part A 10 Note Flapper 10.5A 10a Biological Polymers: DNA Part B Note Flappers 10.7B and 10.7C 10b 10c

71 This study folder is an aid to help you memorize key words/terminologies and definitions. To use this guide simply write the missing word(s) in the empty spaces within each sentence. Some definitions require more description which may need to be in the form of a sentence defining the word(s). Some sections of the chapter ask you to draw pictures and label them. You will need two manila file folders to make your Study Folder. To assemble the Study Folder, begin by cutting out each Chapter Page section along the line labeled CUT HERE then glue that cut out page onto one of the sections of your manila folder. Use the front and back of the tri-fold folder. Some pages have Note Flappers and some have Book Flappers associated with them, and these flappers will be cut out individually. Simply match the TAB number or LABEL on the Note/Book Flapper with the TAB number or LABEL on the chapter page. There are some Note Flappers that STACK on top of each other in some chapters, and these will be labeled as such. This kit contains the Student Note Pages and a Teacher s Answer Key. Chapters 1-5 will be glued onto one folder and Chapters 6-10 onto the second folder. Each tri-fold folder will provide FIVE sections to glue the Chapter Pages onto. A narrower Study Folder cover sheet is included and can be used by the student as the cover for either of the two folders. The cover can be cut out and glued to the front section of either folder. Remember this is YOUR personal Study Folder. Make as many notes in it as you like. Have fun learning! Open your manila folder flat. center Now make two NEW folds about 1/3 away from the center fold. center Glue one cut out Student Chapter Note section to one of the FIVE folded sections. Use both sides of the folder. fold here 1/3 from center original center fold We recommend gluing one Student Chapter Note section at a time as it is being discussed. i

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73 CHAPTER #: CHAPTER 3: CHEMICAL REACTIONS 3.1 Description of a 3.2 Fill in the blanks and write the symbol for each atom on the circles occurs when or more molecules with each other to make a new Also known as ( ) CUT HERE 3.3 occurs when a decomposes or apart, into or more. 3.6 High or current CUT HERE PT Write the name, symbol and atomic number of each on the lines below. GLUE TAB 3.7 HERE Name Symbol Atomic Number 3

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75 Name Date Focus On Middle School Chemistry, Chapter 1 Quiz for Chapter 1, Middle School Chemistry (20 questions, 10 points each, 200 points total) 1. Who is credited for creating the first periodic table? (10 points) Dmitri Mendeleev John Dalton Albert Einstein George Washington 2. Uranium is the heaviest naturally occurring element. (10 points) True False 3. The symbol for lithium is Li. (10 points) True False 4. The word "atom" means... (10 points) Electron Smallest particle Uncuttable Matter 5. The symbol for hydrogen is... (10 points) Hg H Hy He 6. The atomic weight is the sum of the protons and neutrons. (10 points) True False 7. Match the following elements with their symbols (you may use a periodic table). (10 points)

76 Aluminum Sodium Fluorine a. Na b. Al c. H d. F Hydrogen 8. What is the lightest element? (10 points) Helium Lithium Hydrogen Uranium 9. All of the elements in the right hand column of the periodic table are called the alkali metals. (10 points) True False 10. The number of protons for uranium is 92. (10 points) True False 11. Beryllium is an alkaline earth. (10 points) True False 12. Vertically, the elements are arranged according to their chemical properties. (10 points) True False 13. In an atom, the number of protons equals the number of electrons. (10 points) True False 14. What are the first 10 elements in the periodic table going from smallest to largest? (10 points)

77 Oxygen Boron Fluorine Nitrogen Carbon Helium Beryllium Hydrogen Lithium Neon 15. Fluorine is a noble gas. (10 points) True False 16. How many electrons does lithium have? (10 points) Match the description to the proper element. (10 points) Sodium Helium Calcium a. Alkali metal b. Noble gas c. Alkaline earth d. Halogen Fluorine 18. Match the following atomic weights to the proper element (you may use a periodic table). (10 points) Helium Hydrogen a b. 1.0 c d. 4.0

78 Nitrogen e Oxygen Carbon 19. What forms the nucleus, or core, of the atom? (Check all that apply.) (10 points) Orbitals Matter Neutrons Electrons Protons 20. Atoms are composed of which three types of smaller particles? (Check all that apply.) (10 points) Neutrons Matter Electrons Magnitrons Protons Nucleic Acids

79 Answer Sheet Focus On Middle School Chemistry, Chapter 1 Quiz for Chapter 1, Middle School Chemistry (20 questions, 10 points each, 200 points total) Dmitri Mendeleev True True Uncuttable H True b, a, d, c Hydrogen False True True True True 8, 5, 9, 7, 6, 2, 4, 1, 3, 10 False 3 a, b, c, d d, b, c, e, a Neutrons, Protons 20. Neutrons, Electrons, Protons

80 Name Date Focus On Middle School Chemistry, Chapter 3 Quiz for Chapter 3, Middle School Chemistry (20 questions, 10 points each, 200 points total) 1. What type of reaction happens between sodium and chlorine to produce sodium chloride (table salt)? (10 points) Exchange reaction Combination reaction Decomposition reaction Displacement reaction 2. When a reaction occurs, which of the following can happen to the solution? (Check all that apply.) (10 points) It might get colder. It might get hotter. It might release bubbles. It might form a precipitate. 3. What is the breakup of water molecules into hydrogen gas and oxygen gas molecules? (10 points) Exchange reaction Combination reaction Decomposition reaction Displacement reaction 4. A precipitation can look like sand, mud, dust, or snow forming. (10 points) True False 5. What is the formation of sodium hydroxide by two water molecules and two metallic sodium atoms an example of? (10 points) Displacement reaction Exchange reaction Decomposition reaction Combination reaction 6. A spontaneous reaction means it happens all by itself. (10 points)

81 True False 7. A chemical reaction occurs whenever bonds between atoms and molecules are created or destroyed. (10 points) True False 8. The decomposition reaction of water into hydrogen gas and oxygen gas is a spontaneous reaction. (10 points) True False 9. When sodium metal combines with chlorine gas, the combination reaction produces what? (10 points) Hydrogen gas and water Sodium hydroxide and hydrochloric acid Sodium chloride (table salt) Sodium chloride (table salt) and water 10. In a displacement reaction, one atom kicks another atom out of a molecule. (10 points) True False 11. In an exchange reaction, one atom trades places with another atom. (10 points) True False 12. In a decomposition reaction, two or more molecules combine to make a new molecule. (10 points) True False 13. When a reaction occurs, you might observe what type of change? (Check all that apply.) (10 points) Bubbles forming Precipitation Color change Temperature change

82 14. When two water molecules break apart, the decomposition reaction produces what? (10 points) Hydrogen gas and oxygen gas Sodium chloride and water Sodium chloride Sodium hydroxide and hydrochloric acid 15. When a temperature change occurs, a solution only gets hotter. (10 points) True False 16. The reaction between hydrochloric acid and sodium hydroxide is a spontaneous reaction. (10 points) True False 17. Match the result to the proper type of reaction. (10 points) Displacement reaction Combination reaction Exchange reaction a. occurs when one atom trades places with another atom b. occurs when a molecule decomposes, or breaks apart, into two or more molecules c. occurs when one atom kicks another atom out of a molecule d. occurs when two or more molecules combine with each other to make a new molecule Decomposition reaction 18. When hydrogen chloride and sodium hydroxide react, the exchange reaction produces what? (10 points) Sodium chloride (table salt) and water Sodium hydroxide and hydrogen gas Hydrogen gas and oxygen gas Sodium chloride (table salt) 19. In a combination reaction, one atom kicks another atom out of a molecule. (10 points) True False

83 20. The reaction of hydrochloric acid and sodium hydroxide is an example of which type of reaction? (10 points) Exchange reaction Displacement reaction Combination reaction Decomposition reaction Answer Sheet Focus On Middle School Chemistry, Chapter 3 Quiz for Chapter 3, Middle School Chemistry (20 questions, 10 points each, 200 points total) 1. Combination reaction It might get colder., It might get hotter., It might release bubbles., It might form a precipitate. Decomposition reaction True Displacement reaction True True False Sodium chloride (table salt) True True False Bubbles forming, Precipitation, Color change, Temperature change Hydrogen gas and oxygen gas False True c, d, a, b Sodium chloride (table salt) and water False Exchange reaction

84 Name Date Focus On Middle School Chemistry Midterm 1, Chapters 1-5 Midterm quiz for Chapters 1-5, Middle School Chemistry (20 questions, 10 points each, 200 points total) Sample questions Chapters 1 & 3 1. In an atom, the number of protons equals the number of electrons. (10 points) True False 2. What forms the nucleus, or core, of the atom? (Check all that apply.) (10 points) Electrons Orbitals Neutrons Matter Protons 3. Match the following atomic weights to the proper element (you may use a Periodic Table). (10 points) Nitrogen Carbon Oxygen a b c. 1.0 d e. 4.0 Helium Hydrogen 4. Match the following description to the proper element. (10 points) Calcium Fluorine Helium a. Alkali metal b. Halogen c. Alkaline earth d. Noble gas Sodium

85 9. Match the result to the proper type of reaction. (10 points) Combination reaction Decomposition reaction Displacement reaction a. occurs when one atom trades places with another atom b. occurs when one atom kicks another atom out of a molecule c. occurs when two or more molecules combine with each other to make a new molecule d. reaction occurs when a molecule decomposes, or breaks apart, into two or more molecules Exchange reaction 10. When a reaction occurs, you might observe what type of change? (Check all that apply.) (10 points) Temperature change Color change Bubbles forming Precipitation 11. A chemical reaction occurs whenever bonds between atoms and molecules are created or destroyed. (10 points) True False 12. The decomposition reaction of water into hydrogen gas and oxygen gas is a spontaneous reaction. (10 points) True False

86 Answer Sheet Focus On Middle School Chemistry Midterm 1, Chapters 1-5 Midterm quiz for Chapters 1-5, Middle School Chemistry (20 questions, 10 points each, 200 points total) Sample questions Chapters 1 & True Neutrons, Protons a, d, b, e, c c, b, d, a c, d, b, a Temperature change, Color change, Bubbles forming, Precipitation True 12. False

87 GRAPHICS

88 Illustrations: Janet Moneymaker Copyright 2017 Gravitas Publications, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. No part of this book may be used or reproduced in any manner whatsoever without written permission. Focus On Middle School Chemistry Graphics Package Published by Gravitas Publications Inc. Real Science-4-Kids

89 Focus On Middle School Chemistry

90 Increasing atomic number All of the elements in a single column have similar properties. Focus On Middle School Chemistry