Living By Chemistry. Unit 1: ALCHEMY Matter, Atomic Structure, and Bonding

Transcription

1 Living By Chemistry Unit 1: ALCHEMY Matter, Atomic Structure, and Bonding

2 In this unit you will learn: what matter is composed of to use the language of chemistry to decode information contained in the periodic table how new substances with new properties are made what holds substances together

3 Section I: Defining Matter Lesson 1 Tools of the Trade Lesson 2 A Penny for Your Thoughts Lesson 3 What s the Matter? Lesson 4 Mass Communication Lesson 5 All That Glitters

4 Lesson 1: Tools of the Trade Lab Equipment and Safety recognize common chemistry tools and equipment that you will be using in the course find all the safety equipment in the laboratory and understand its use understand the rules of safety in the chemistry laboratory

5 Discussion Notes Safety Equipment: fire blanket fire extinguisher eye wash safety goggles First aid kit Aprons/lab coat Shower hood Safety behaviors: Chemistry labs have a number of potential hazards! Know the procedures Use all chemicals properly No horseplay Keep lab area neat/clean Watch hair/clothing around flames

6 Lesson 2: A Penny for Your Thoughts Introduction to Chemistry Key Question What is chemistry?

7 Long ago, early scientists tried to turn ordinary things into gold. This pursuit was called alchemy, and the people who engaged in alchemy were called alchemists.

8 You will be able to: observe a procedure and write observations define and formulate a hypothesis to explain observed phenomena define chemistry and begin to describe what chemists study

9 What is Chemistry? The study of substances, their properties, and how they can be transformed. The study of matter and how matter can be changed.

10 CHEMISTRY Let s Do

11 A Penny for your Thoughts Purpose: observe a chemical transformation. Do you think you changed the penny to gold? How would you be able to tell for sure?

12 Discussion Notes To determine whether the new penny is gold, you need to study its properties. Property: A characteristic of a substance. Matter has observable and measurable qualities. We can use general properties to identify substances.

13 All substances have properties Example: People can be identified by their Face (shape, expressions) Voice Height Finger prints Eye color Hair color Teeth DNA

14 Properties are used to identify, describe and classify matter. Physical Properties: Characteristic of a substance that can be observed without changing the substance into something else. for example: mass, color, hardness, size, texture, odor Chemical Properties: characteristics involved when a substance interacts with another substance to change its chemical make-up. for example: ph, flammability, rusting (oxidizing), gassing

15 examples of physical properties commonly used in chemistry: state, freezing point, boiling point, melting point, viscosity, density, luster and many more. viscosity - The resistance of a liquid to flowing. Low viscosity-water, rubbing alcohol High viscosity-honey

16 Physical properties of matter are categorized as either: Intensive or Extensive: Intensive - Properties that do not depend on the amount of the matter present. color, odor, luster malleability, ductility, conductivity density Extensive Properties that change when the size of the sample changes. mass, volume, length total charge

17 Chemical properties A common chemical property is reactivity. Reactive to oxygen Reactive to air Reactive to water Note that chemical properties aren t EASY to observe, unlike physical properties.

18 examples of chemical properties commonly used in chemistry: Flammability, corrosivity, oxidation state, and more oxidation - The loss of electrons. When a substance is oxidized, it s properties change for example silver tarnishes metals rust

19 Did you know? Fruit exposed to the air is oxidized (the oxygen steals electrons from the compounds in the fruit s cells) and turns brown. The process is very similar to the rusting process of metals. The oxidized form of these compounds is different from the unoxidized form and is, unfortunately, unappealing to eat.

20 antioxidants Many 'superfoods' are advertised as containing antioxidants. An antioxidant is a compound that reduces the oxidation of other compounds. In theory, consuming antioxidants will help our bodies fight off the harmful effects of oxidation, keeping our cells and enzymes happy and healthy. In other words, eating things like blueberries and chocolate will help our insides from looking like browning fruit.

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23 How do you know if it is a chemical or physical property? Do you think you changed the penny to gold? How would you be able to tell for sure? If it can Change and can t be reversed, it s CHemical

24 More discussion Notes in text.. Scientists use a systematic approach to solve problems in science. Hypothesis: A testable prediction or explanation for an observation. If I changed the copper into gold, then the penny will exhibit physical and chemical properties associated with the element gold.

25 Lesson 2 summary: What is chemistry? Chemistry is the study of what substances are made of, how they behave, and how they can be transformed. It is the study of matter and how matter can be changed. Matter can be identified by its chemical and physical properties. A hypothesis is a testable explanation for an observation. Scientists use a systematic approach to solving problems in science.

26 Lesson 3: What s the Matter? Defining Matter You will be able to: define matter classify an item as matter or not matter

27 Remember? 1. How do we define matter? 2. Name two things that are matter and two things that are not matter.

28 Discussion Notes Items that are clearly matter are all objects, or things, that are tangible. Energy and ideas are not matter, but they involve matter. Matter has some sort of dimension and substance to it.

29 A good definition should work 100% of the time. Here are some textbook definitions of matter: Matter: Anything that has substance and takes up space. Matter: Anything that has mass and volume. wind music clouds

30 Everything that has mass and takes up space is matter, yet some things do not consist of matter. Here is a list of 10 examples of non-matter. Basically, any type of energy or any abstract concept is an example of something that is not matter. time light love gravity heat information sound color thoughts microwaves memories reflections

31 Why aren t light and heat matter? The universe consists of matter and energy. The Conservation Laws state that the total amount of matter and energy are constant in a reaction, but matter and energy may change forms. Energy describes the ability to cause change. While matter may have energy, they are different from each other. One easy way to tell matter and energy apart is to ask yourself whether what you observe has mass. If it doesn't, it's energy!

32 Examples of energy include any part of the electromagnetic spectrum, which includes visible light, infrared, ultraviolet, x-ray, microwaves, radio, and gamma rays. Other forms of energy are heat (which may be considered infrared radiation), sound, potential energy, and kinetic energy.

33 Another way to distinguish between matter and energy is to ask whether something takes up space. Matter takes up space. You can put it in a container. While gases, liquids, and solids take up space, light and heat do not.

34 Usually matter and energy are found together, so it can be tricky to distinguish between them. For example, a flame consists of matter in the form of ionized gases and particulates and energy in the form of light and heat. You can observe light and heat, but you can't weigh them on any scale.

35 summary Chemists study all kinds of matter. Matter is everything that has substance and takes up space, or that has mass and volume. Your brain is an example of matter, ideas are not.

36 Lesson 4: Mass Communication Mass and Volume

37 Would it hurt more to be hit with 5 pounds of feathers or 5 pounds of bricks?

38 Key concept How do you determine the masses and volumes of different substances? Skills to master: measure mass using a balance measure the volume of regularly and irregularly shaped objects

39 Discussion Notes Mass is commonly measured in units of grams (g) or kilograms (kg). 1 kg = 1000 g

40 Discussion Notes (cont.) Volume is a measure of the amount of space occupied by something ml = 1 L 1 ml = 1 cm 3 Mass: A measure of the quantity of matter in an object. Volume: The amount of space a sample of matter occupies

41 Prepare for the Lab In this lab, you will be measuring volume with a graduated cylinder or calculating directly based on formulas for volume of solids. To the nearest hundredth of a milliliter, the volume of liquid is 5.52 ml.

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43 If a solid is rectangular or cylindrical, you can find its volume by measuring its dimensions and using a geometric formula.

44 remember: volume is a measurement of the amount of space a substance occupies. Measuring volume using displacement method

45 summary How do you determine the masses and volumes of substances? Mass is a measure of the amount of substance. Mass can be measured using an electronic or triple beam balance. Volume is the amount of space occupied by an object. The volume of a liquid can be measured in a graduated cylinder. Objects with similar volumes can have different masses, and vice versa.

46 post note: Significant digits Indicates the accuracy of the measuring instrument. Exact measurement plus one estimate.

47 Determining The Correct Number Of Significant Digits After performing a calculation, we often obtain more digits than are warranted by the measurements that produced it. In order to determine the correct number of significant digits in the answer, there are two different methods depending on which mathematical operation was performed. Get chemistry help.

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49 Check-in A penny has a mass of g. a. What is the mass to the nearest tenth of a gram? b. How would you determine the volume of a penny? c. What is the difference between mass and volume? d. Suppose you find that the golden penny has a mass of 2.6 g. If you compare it with the mass of this penny, what can you conclude?

50 Lesson 5: All That Glitters Density

51 Key Question How can you use mass and volume to determine the identity of a substance? You will be able to: define density as the amount of mass in a certain space, or mass per unit volume solve problems for density, mass, or volume using the equation D = m/v explain how and why density can be used to identify a substance.

52 Discussion Notes Density is an extensive property of matter.

53 Discussion Notes Common materials and their densities. Material Density Material Density zinc 7.1 g/cm 3 gold 19.3 g/cm 3 paper 0.9 g/cm 3 brass 8.4 g/cm 3 water 1.0 g/ml copper 9.0 g/cm 3 aluminum 2.7 g/cm 3 lead 11.4 g/cm 3

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55 density Additional analysis: Line of best fit determine unknown

56 summary How can you use mass and volume to determine the identity of a substance? One substance can be distinguished from another by examining its intensive physical properties, such as density. Density is a measure of the mass per unit volume of a substance. The density of any given substance is always the same (as long as the temperature remains constant).

57 How could you use density to find out the composition of a penny? What year did the penny composition change? How thick is a piece of aluminum foil?

58 Check-in In 1999, the United States Mint produced a coin called the Golden Dollar. It features an image of Sacagawea, the famous Native American guide for Lewis and Clark. It has a mass of 9.8 g and volume of 1.1 ml. Is this coin truly gold? Explain. (The density of gold is 19.3 g/ml.)