Ch 1 (Part 1: Matter) Page 1

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1 Introduction Walk through syllabus: Class schedule Syllabus Office hours Required materials Grading Lab policy Goggles for the third lab Introduce course web page Homework policy introduce Mastering Chemistry Study Habits Why study chemistry? (Required by major, love of science, etc.) What do you need to be prepared to take this class? Algebra 1 What should you bring? refer to syllabus How much time should it take you? (16-18 hrs per week avg. total) Mention Beacon Program 2 hr commitment per week average 1 letter grade higher rewarded by up to a maximum of 14 pts based on attendance and effort. Student Profiles Found on website. only fill in personal info you are comfortable with. Turn in during extra credit into. (first 3 weeks of school) Ch 1 (Part 1: Matter) Page 1

2 Chapter 1 Matter & Measurement Part 1: Matter 1.1 Chemistry the Central Science What is chemistry? : the study of nature, properties & transformations of matter. : Anything that has mass and occupies space. (The stuff around us) Chemistry is often referred to as the Central Science. (Show in ppt) Multiple sub-disciplines organic based compounds All other elements Study of biological chemicals Methods of Analysis Ch 1 (Part 1: Matter) Page 2

3 The study of chemistry follows the: Scientific Method. review what is already known, make observations & experimental information. A tentative explanation or prediction of previous observations. Gather: qualitative data and quantitative data that would help to confirm or invalidate the hypothesis. You should try to in the theory! and possibly revise or reject the original hypothesis. Famous quote: There are 2 possible outcomes: If the result confirms the hypothesis, then you've made a measurement. If the result is contrary to the hypothesis, then you've made a discovery. -Enrico Fermi How can we describe matter more specifically? Chemical and Physical Properties Physical Property A characteristic that can be observed without changing the of the substance. (e.g., size, color, weight) Qualitative Quantitative Ch 1 (Part 1: Matter) Page 3

4 Chemical Property Describes how a substance with other substances. These result in a change in the composition of a material as a result of a chemical reaction. Problem: Are the following examples of chemical or physical properties? Lead is denser than aluminum oxygen gas supports combustion Water boils below 100 degrees at high altitudes Physical and Chemical Changes Physical Changes type? alter the chemical makeup of a substance. e.g., Phase changes are examples of physical changes. For example Water (H 2 O) Ch 1 (Part 1: Matter) Page 4

5 Chemical Changes alter the chemical makeup. They involve a chemical reaction e.g., a nail rusting or burning the fuel in your car. Methane + oxygen gives carbon dioxide + water CH4 + 2 O2 CO2 + 2 H2O Problem: Are the following examples of chemical or physical changes? Type of Change? Milk turning sour making wine from grapes water freezing plants undergoing photosynthesis helium leaking out of a balloon 1.2 States of Matter States of Matter Matter exists in three phases; Phase depends on temperature and pressure - A substance that has a definite shape and volume. - A substance that has a definite volume but assumes the shape of its container. - A substance that has neither a definite volume nor a definite shape. Ch 1 (Part 1: Matter) Page 5

6 Changes of State to go from a liquid to a solid to go from a solid to a liquid to go from a liquid to a gas to go from a gas to a liquid to go directly from a solid to a gas to go from a gas directly to a solid Problem: Acetic acid, (which gives the sour taste to vinegar), has a melting point of 16.7 C and a boiling point of 118 C. Predict the physical state of acetic acid when the ambient temperature is 10 C. Ch 1 (Part 1: Matter) Page 6

7 Butane has a melting point of C and a boiling point of -0.5 C. What is the state of butane at room temperature, which is 25 C? a. gas b. liquid c. solid d. can t tell from the given information. 1.3 Classification of Matter Pure Substances vs Mixtures A sample consisting of only either an elements or compounds. (Definitions to follow.) Unique set of properties Cannot be separated into parts by a. e.g. pure gold, pure water, pure table salt. A combination of pure substances. Each of the constituents retain their identity (They do not enter into a reaction) Can be separated into parts by a physical change. mixtures have a uniform appearance and composition throughout (mayonnaise, homogenized milk, salt water). Mixtures do not have a uniform appearance and composition throughout (gravel, cookie dough) Which of these is a pure substance: sodium metal, solid sodium chloride, sodium chloride dissolved in water? a. All are pure substances. b. None are pure substances. c. Only sodium metal is a pure substance. d. Sodium metal and solid sodium chloride are pure substances. Pure substances can be classified into two groups: Ch 1 (Part 1: Matter) Page 7

8 Elements vs Compounds Fundamental building block from which all matter is derived. Each element is characterized by its unique properties Cannot be broken down into any simpler substance. Individual elements are made up of the same kinds of atoms are the smallest unit of an element that retains the properties of the element. All elements can be found on the Periodic Table of Elements. Examples: Pure substances that can be broken down chemically into simpler substances. (elements) Combination of two or more different elements in definite proportions Properties are unique to the compound and different of its constituent elements. are the smallest unit of a pure compound that retains the properties of the compound. Examples: Which of the following is NOT a compound? Co, CO, CO 2, CN a. Only Co is not a compound. b. Co and O2 are not compounds. c. Co, CO, and CN are not compounds. d. Co, CO2, and CN are not compounds. Example of a process that would break up a compound into its elements: Ch 1 (Part 1: Matter) Page 8

9 Water can be chemically changed and separated into hydrogen and oxygen. The reactant (water) is written on the. The products (hydrogen and oxygen) are written on. An connects the two parts to indicate a chemical reaction. The conditions necessary are written above the arrow. Problem: Classify each of the following as a mixture or a pure substance. If a mixture decide homogeneous or heterogeneous. If a pure substance decide compound or element. (a) Vanilla ice cream Made up of more than one substance cream, sugar, and vanilla flavoring. The composition appears to be uniform throughout. - (b) Sugar Made up of only one kind of matter, pure sugar. It is not on the periodic table, so it is not an element. Ch 1 (Part 1: Matter) Page 9

10 1.4 Chemical Elements and Symbols Chemical Symbols There are currently 118 identified elements. 91 occur naturally. The rest have been man-made. letters long. First letter is Second letter (if present) is Most are based on current names (e.g., carbon = ; calcium = ) Some are based on old Greek or Latin names Pb = plumbum (lead) like plumbers (use lead pipes) Na = natrium (sodium) Ch 1 (Part 1: Matter) Page 10

11 54 Elements to Know Aluminum Al 13 Manganese Mn 25 Antimony Sb 51 Mercury Hg 80 Argon Ar 18 Molybdenum Mo 42 Arsenic As 33 Neon Ne 10 Barium Ba 56 Nickel Ni 28 Beryllium Be 4 Nitrogen N 7 Bismuth Bi 83 Oxygen O 8 Boron B 5 Phosphorus P 15 Bromine Br 35 Plutonium Pu 94 Cadmium Cd 48 Potassium K 19 Calcium Ca 20 Radium Ra 88 Carbon C 6 Radon Rn 86 Cesium Ce 55 Rubidium Rb 37 Chlorine Cl 17 Selenium, Se 34 Chromium Cr 24 Silicon Si 14 Cobalt Co 27 Silver Ag 47 Copper Cu 29 Sodium Na 11 Fluorine F 9 Strontium Sr 38 Gold Au 87 Sulfur S 16 Helium He 2 Thallium Tl 81 Hydrogen H 1 Tin Sn 50 Iodine I 53 Titanium Ti 22 Iron Fe 26 Tungsten W 74 Krypton Kr 36 Uranium U 92 Lead Pb 82 Vanadium V 23 Lithium Li 3 Xenon Xe 54 Magnesium Mg 12 Zinc Zn 30 You are not responsible for knowing the element numbers. They are in the table to help you find them on the periodic table. Ch 1 (Part 1: Matter) Page 11

12 Not all elements occur with equal abundance. Chemical Formulas Just as elements combine to form compounds, Chemical symbols combine to form chemical formulas. Subscripts are used to show how many atoms of each element are given in a chemical compound. If there are parentheses in the formula, the subscript on the outside of the ( ) x is the multiplier of everything inside the parentheses. Problem: how many elements of each type are in one formula unit of Al 2 (S 2 O 3 ) 3? Ch 1 (Part 1: Matter) Page 12

13 How many atoms of hydrogen are in one molecule of isopropyl alcohol, (CH 3 ) 2 CHOH? a. five b. six c. seven d. eight From Table 1.4 Essential Elements for Human Life Element Symbol Function calcium chromium iodine iron potassium selenium teeth and bones carbohydrate metabolism thyroid function oxygen carrying ability of blood electrolytes and nerve action fat metabolism Molecules Identifiable units made up of combined in a definite ratio, If atoms are the same, (e.g., O 2, H 2, P 4 ) they combine to make an. If atoms are different, (e.g., H 2 O), they combine to make a. 7 elements are (come in pairs when pure elements) N 2(g), O 2(g), F 2(g), Cl 2(g), Br 2(l), I 2(s) Note that they 6 of the 7 form the number 7 when placed on the Periodic Table. Ch 1 (Part 1: Matter) Page 13

14 1.5 Chemical Reactions: An example of Chemical Change. Reactions The process of ethanol burning in oxygen is an example of a chemical reaction. We can write a chemical equation to show what is happening in the reaction: OR CH 3 CH 2 OH + 3O 2 2 CO H 2 O Nickel Metal can be placed in a solution of hydrochloric acid. The acid will eat away (react with) the nickel. The solution will turn green and bubbles will form. We know a reaction has happened because: Change in dissolving of Appearance of Ch 1 (Part 1: Matter) Page 14