Welcome to General Chemistry I

Chemistry Chemistry is a branch of science that studies the composition and properties of matter and the changes it undergoes H 2 O http://theresilientearth.com/?q=content/climate-models-blown-away-water-vapor 2

CLASSIFICATION OF MATTER 3

Matter Matter is anything that has mass and takes up space 4

States of Matter The three states of matter are 1) solid 2) liquid 3) gas In this figure, those states are ice, liquid water, and water vapor 5

States of Matter 6

Classification of Matter by Composition 7

Classification of Matter by Composition http://f.tqn.com/y/chemistry/1/s/c/k/2/tomato-mixture.jpg 8

Classification of Matter by Composition Heterogeneous mixture Heterogeneous Has two or more visibly distinct phases Each phase has different properties Mixture contains two or more substances that are mixed together contain substances that have not reacted chemically with each other Can be separated by physical methods http://f.tqn.com/y/chemistry/1/s/c/k/2/tomato-mixture.jpg 9

Classification of Matter by Composition http://f.tqn.com/y/chemistry/1/s/c/k/2/tomato-mixture.jpg 10

Classification of Matter by Composition Milk is a liquid with bits of solid particles floating around; if you let it sit, the particles will separate. https://upload.wikimedia.org/wikipedia/commons/a/ad/glass_of_milk_on_tablecloth.jp 11

Classification of Matter by Composition Homogeneous mixture Homogeneous Contains one visible distinct phase Contains uniform properties throughout Mixture contains two or more substances that are mixed together contain substances that have not reacted chemically with each other Can be separated by physical methods https://upload.wikimedia.org/wikipedia/commons/a/ad/glass_of_milk_on_tablecloth.jpg 12

Classification of Matter by Composition 13

Classification of Matter by Composition Pure substance made up of one type of particle Particle of water is H 2 O ( a compound) Particle of gold is Au (an element) 14

Classification of Matter by Composition 15

Classification of Matter by Composition Element Pure substance that can not be broken down into two or more pure substances 16

Classification of Matter by Composition 17

Classification of Matter by Composition Compound Pure substance that can be broken down into two or more pure substances 18

Methods of Classification of Matter 1. State of Matter A. Solid B. Liquid C. Gas 2. Composition of Matter A. Element B. Compound C. Mixture 19

PROPERTIES OF MATTER 20

Types of Changes Physical Changes Chemical Changes 21

Types of Changes Physical Changes are changes in matter that do not change the composition of a substance Examples include changes of state, temperature, and volume 22

Types of Changes Converting between the three states of matter is a physical change When ice melts or water evaporates, there are still 2 Hydrogen Why? atoms and 1 Oxygen atom in each molecule 23

Types of Changes Converting between the three states of matter is a physical change When ice melts or water evaporates, there are still 2 Hydrogen atoms and 1 Oxygen atom in each molecule 24

Types of Changes Physical Changes are changes in matter that do not change the composition of a substance Examples include changes of state, temperature, and volume Chemical Changes result in new substances Examples include combustion, oxidation, and decomposition 25

Types of Changes A chemical reaction is a chemical change Elements hydrogen and oxygen become water 26

Standardized system of measurement, based on decimal notation METRIC SYSTEM OF UNITS 27

Measurements Observations may be: Qualitative Quantitative 28

Quantitative (Numerical) Data Obtained by measurement Length Volume Mass 29

Metric System: Base Units Table 1.4 on page 14 lists base units Length meter (m) Volume Mass kilogram (kg) 30

Metric System of Units: Prefixes Table 1.5 on page 14 31

Metric System of Units: Prefixes 32

Metric System of Units: Prefixes 1 m 10 cm 1 cm 1 mm 100 mm 10 mm 1 mm 100 nm 10 nm 1 nm 0.1 nm https://owlspace-ccm.rice.edu/portal/site/chem-570-001-sp07/page/ea15aaa6-a000-41db-00ac-6d32817b0a23 33

Metric System: Base Units Table 1.4 on page 14 lists base units Length meter (m) Volume? Mass kilogram (kg) 34

Metric System: Derived Base Units Volume Derived Unit Base unit liter (L) 1 dm 3 = 1 L 1 cm 3 = 1 ml Volume Liter (L) 35

Metric System: Derived Base Units Density is the amount of mass that fills a space less dense more dense http://images.sciencesource.com/preview/14974852/bx5834.html 36

Density Density is the amount of mass that fills a space Derived Unit Expressed as g/ml or g/cm 3 Temperature dependent http://images.sciencesource.com/preview/14974852/bx5834.html 37

Density Density is the amount of mass that fills a space Calculate density of mercury if 1.00 x 10 2 g occupies 7.36 cm 3 mass = 1.00 x 10 2 g volume = 7.36 cm 3 38

UNCERTAINTY IN MEASUREMENT 39

Quantitative (Numerical) Data Obtained by measurement Length Volume Mass 40

Quantitative (Numerical) Data Measurement is inexact, which leads to uncertainty Length Volume Mass 41

Measurements: Uncertainty Uncertainty is degree of doubt about reading Only record one estimated (uncertain) digit in a measurement 29.2 => 29.1 29.3 29.25 => 29.24 29.26 42

Measurements: Significant Figures Digits in a measurement that are known to a certainty plus one that is estimated (uncertain) All certain digits + One uncertain digit # of Significant Figures 29.2 29.25 43

Measurements Precise: measurements are closely cluster about a single value Accurate: measurements clustered around true value 44

Measurements Precise: measurements are closely cluster about a single value Accurate: measurements clustered around true value 45

DETERMINING SIGNIFICANT FIGURES 46

Significant Figures Rule 1: Digits 1 9 are always significant figures 47

Significant Figures Rule 1: Digits 1 9 are always significant figures How many significant figures in the numbers below? 1 145 123.432 48

Significant Figures Rule 2: Zeros at the beginning of a number are not significant 49

Significant Figures Rule 2: Zeros at the beginning of a number are not significant How many significant figures in the numbers below? 01 0.145 0.00000458 50

Significant Figures Rule 3: Zeros in-between nonzero digits are significant figures 51

Significant Figures Rule 3: Zeros in-between nonzero digits are significant figures How many significant figures in the numbers below? 401 0.1045 0.045008 52

Significant Figures Rule 4: Zeros at a end of a number are only significant if there is a decimal point in number 53

Significant Figures Rule 4: Zeros at a end of a number are only significant if there is a decimal point in number How many significant figures in the numbers below? 10 40.050 0.02000100 54

Mathematical operations should not increase or decrease uncertainty of measurements SIGNIFICANT FIGURES AND MATHEMATICAL OPERATIONS 55

Operational Rules for Mathematical Operations Rule 1: In multiplication and division operations, the number of significant figures in the answer is the same as the number in the calculation with the fewest significant digits 2.456 x 1.2 = 2.9472 (calculator answer) = 2.9 (correct answer) 56

Operational Rules for Mathematical Operations Rule 2: In addition and subtraction operations, number of decimal places in answer is equal to number with fewest decimal places 2546 Ones Position + 2.546 thousandth position + 25.46 hundredth position 2574 57

Operational Rules for Mathematical Operations Exact numbers contain no uncertainty; do not apply significant figures to them Counted numbers (number of eggs in a dozen) Simple fractions (1/4) Always round the answer to the correct number of significant digits 58

Rounding off numbers Process of deleting unwanted digits Rule 1: In a series of calculations, carry the extra digits through to the final result, then round Rule 2: If the first digit to be dropped is less than 5, that digit and all that follow are dropped 52.145 rounded to 3 significant figures is 52.1 59

Rounding off numbers Process of deleting unwanted digits Rule 3: If the first digit to be dropped is equal to or greater than 5 the last retained digit increased by 1 52.675 rounded to 3 significant figures is 52.7 60

DIMENSIONAL ANALYSIS 61

Dimensional Analysis: Conversion Factors Conversion Factor A ratio (or fraction) which represents the relationship between two different units 1 min = 60 sec It is ALWAYS equal to 1 Allows you to change units while maintaining your original measurements 62

Mathematical Operations: Conversion Factors Conversion Factor A ratio (or fraction) which represents the relationship between two different units 1 min = 60 sec It is ALWAYS equal to 1 1 min= 60 sec 1 min= 1 60 sec 60 sec 60 sec Allows you to change units while maintaining your original measurements 63

Mathematical Operations: Conversion Factors Conversion Factor A ratio (or fraction) which represents the relationship between two different units 1 min = 60 sec It is ALWAYS equal to 1 1 min= 60 sec 1 min = 1 60 sec 60 sec 60 sec Allows you to change units while maintaining your original measurements 64

Dimensional Analysis Procedure for converting a measurement in one unit to an equivalent measurement in another unit Step 1: Identify known/given unit and unit desired given unit desired unit Step 2: Multiply known/given unit by conversion factor(s) to get the desired unit Step 3: Check that all unwanted units cancel out and result have correct number of significant figures 65

Dimensional Analysis Single Conversion Step 1: convert inches to centimeters Step 2: Is the conversion a. Metric-to-Metric b. English-to-English c. English-to-Metric d. Metric-to-English Given unit Desired unit 66

Dimensional Analysis Procedure for converting a measurement in one unit to an equivalent measurement in another unit Step 1: Identify known/given unit and unit desired given unit desired unit Step 2: Multiply known/given unit by conversion factor(s) to get the desired unit x Step 3: Check that all unwanted units cancel out and result have correct number of significant figures Conversion Factor 67

Dimensional Analysis Procedure for converting a measurement in one unit to an equivalent measurement in another unit Step 1: Identify known/given unit and unit desired given unit desired unit Step 2: Multiply known/given unit by conversion factor(s) to get the desired unit x Step 3: Check that all unwanted units cancel out and result have correct number of significant figures x 70

Dimensional Analysis Single Conversion Step 1: convert inches to centimeters Step 3: Given unit Desired unit Is the conversion factor exact or not exact? 71

Dimensional Analysis Single Conversion Step 1: convert inches to centimeters Step 3: Given unit Desired unit Is the conversion factor exact or not exact? 72

Dimensional Analysis Single Conversion Step 1: convert inches to centimeters Step 3: Given unit Desired unit Is the conversion factor exact or not exact? 73

Dimensional Analysis Two Conversions Step 1: convert millimeters to centimeters Step 2: Is the conversion a. Metric-to-Metric b. English-to-English c. English-to-Metric d. Metric-to-English Given unit Desired unit 75

Dimensional Analysis Procedure for converting a measurement in one unit to an equivalent measurement in another unit Step 3: Check that all unwanted units cancel out and result have correct number of significant figures x 80

Dimensional Analysis Two Conversions Step 1: convert millimeters to centimeters Step 3: Given unit Desired unit Is the conversion factor exact or not exact? 81

Dimensional Analysis Two Conversions Step 1: convert millimeters to centimeters Step 3: Given unit Desired unit Is the conversion factor exact or not exact? 82

Dimensional Analysis Two Conversions Step 1: convert millimeters to centimeters Step 3: Given unit Desired unit Is the conversion factor exact or not exact? 83

Calculate volume of 65.0 g of wood alcohol if the density is 0.791 g/ml This is a dimensional analysis 84

Dimensional Analysis Procedure for converting a measurement in one unit to an equivalent measurement in another unit Step 1: Identify known/given unit and unit desired given unit desired unit Step 2: Multiply known/given unit by conversion factor(s) to get the desired unit x Step 3: Check that all unwanted units cancel out and result have correct number of significant figures x 85

Calculate volume of 65.0 g of wood alcohol if the density is 0.791 g/ml Step 1: g/ml, ml and g http://images.sciencesource.com/preview/14974852/bx5834.html 86

Calculate volume of 65.0 g of wood alcohol if the density is 0.791 g/ml Step 1: g/ml, ml and g Given unit Desired unit What is the conversion factor? http://images.sciencesource.com/preview/14974852/bx5834.html 87

Calculate volume of 65.0 g of wood alcohol if the density is 0.791 g/ml Step 1: g/ml, ml and g Step 2: Step 3:??? http://images.sciencesource.com/preview/14974852/bx5834.html 88

Calculate volume of 65.0 g of wood alcohol if the density is 0.791 g/ml Step 1: g/ml, ml and g Step 2: Step 3: http://images.sciencesource.com/preview/14974852/bx5834.html 89

What is the mass in grams of a cube of gold (d = 19.32 g/cm 3 ) if the length of the cube is 2.00 cm? Step 1: g, cm and g/cm 3 http://images.sciencesource.com/preview/14974852/bx5834.html 90

What is the mass in grams of a cube of gold (d = 19.32 g/cm 3 ) if the length of the cube is 2.00 cm? Step 1: g, cm and g/cm 3 Given unit Desired unit What is the conversion factor? http://images.sciencesource.com/preview/14974852/bx5834.html 91

What is the mass in grams of a cube of gold (d = 19.32 g/cm 3 ) if the length of the cube is 2.00 cm? Step 1: g, cm and g/cm 3 Step 2: 2.00 cm Step 3:??? http://images.sciencesource.com/preview/14974852/bx5834.html 92

What is the mass in grams of a cube of gold (d = 19.32 g/cm 3 ) if the length of the cube is 2.00 cm? Step 1: g, cm and g/cm 3 Step 2: 2.00 cm Step 3: http://images.sciencesource.com/preview/14974852/bx5834.html 93

TEMPERATURE 94

Temperature Measures the heat or lack of heat in an object 3 different temperature scales Celsius o C = 5/9( o F - 32) o C = K 273.15 Kelvin K = o C + 273.15 Fahrenheit o F = (9/5) o C + 32 95

Temperature Measures the heat or lack of heat in an object 3 different temperature scales Celsius o C = 5/9( o F - 32) o C = K 273.15 Kelvin K = o C + 273.15 Fahrenheit o F = (9/5) o C + 32 If a weather forecaster predicts that the temperature for the day will reach 31 o C, what is the predicted temperature in o F? 96