1. Chapter 1 Chemistry: The Study of Matter

2. What is Chemistry? The study of matter, its composition, properties, and the changes it undergoes Applied Chemistry is the using of chemistry to attain certain goals, in fields like medicine, agriculture, and manufacturing Pure Chemistry gathers knowledge for knowledge sake

3. Branches of Chemistry Analytical Chemistry -studies composition of substances. Organic Chemistry -compounds containing carbon Inorganic Chemistry -substances without carbon Biochemistry- Chemistry of living things Physical Chemistry studies behavior of substances rates and mechanisms of reactions energy transfers

4. Chemistry is A natural science A language with its own vocabulary A way of thinking

5. Scientific Method A way of solving problems or answering questions Starts with observation- noting and recording facts Hypothesis- an educated guess as to the cause of the problem or answer to the question

6. Scientific Method Experiment- designed to test the hypothesis Only two possible answers 1) hypothesis is right 2) hypothesis is wrong Generates data observations from experiments Modify hypothesis- repeat the cycle

7. Variables Controlled experiment- Only want one thing to change at a time in a laboratory. Manipulated variable- What you change or control directly Also called independent variable Responding variable – What changes as a result. No direct control Also called dependent variable

8. Prediction Experiment Modify Observations Hypothesis Experiment Law Theory (Model)

9. Observations Hypothesis Experiment Cycle repeats many times. The hypothesis gets more and more certain. Becomes a theory A thoroughly tested model that explains why things behave a certain way.

10. Theory can never be proven. Useful because they predict behavior Help us form mental pictures of processes (models) Observations Hypothesis Experiment

11. Another outcome is that certain behavior is repeated many times Scientific Law is developed Description of how things behave Law - how Theory- why Observations Hypothesis Experiment

12. Law Theory (Model) Prediction Experiment Modify Observations Hypothesis Experiment

13. Law vs. Theory Theory can’t be proved; always the possibility that a new experiment will disprove a theory Law described a natural phenomenon, but does not attempt to explain it

14. Frame of Reference What is it? Physics Definition- system of objects that are not moving with respect to one another Dictionary Definition- set of ideas, facts, or circumstances within which something exists. What does Frame of Reference mean to the world of Chemistry?

15. What is Matter? Matter is anything that takes up space and has mass Mass is the amount of matter in an object Mass is resistance to change in motion along a smooth and level surface

16. Types of Matter Substance- a particular kind of matter – pure Mixture- more than one kind of matter

17. © 2009, Prentice- Hall, Inc. Matter We define matter as anything that has mass and takes up space.

18. © 2009, Prentice- Hall, Inc. Matter Atoms are the building blocks of matter.

19. © 2009, Prentice- Hall, Inc. Matter Atoms are the building blocks of matter. Each element is made of the same kind of atom.

20. © 2009, Prentice- Hall, Inc. Matter Atoms are the building blocks of matter. Each element is made of the same kind of atom. A compound is made of two or more different kinds of elements.

21. © 2009, Prentice- Hall, Inc. Classification of Matter

22. © 2009, Prentice- Hall, Inc. Properties and Changes of Matter

23. Properties Words that describe matter (adjectives) Physical Properties- a quality or condition of a substance that can be observed or measured without changing the substance’s composition Chemical Properties- a property that can be observed by changing the type of substance

24. © 2009, Prentice- Hall, Inc. Types of Properties Intensive Properties… Are independent of the amount of the substance that is present. Density, boiling point, color, etc. Extensive Properties… Depend upon the amount of the substance present. Mass, volume, energy, etc.

25. Examples of Physical Properties 1) Color 2) Solubility 3) Odor 4) Hardness 5) Density 6) Melting Point 7) Boiling Point 8) Size 9) Shape

26. © 2009, Prentice- Hall, Inc. Types of Changes Physical Changes These are changes in matter that do not change the composition of a substance. Changes of state, temperature, volume, etc. Chemical Changes Chemical changes result in new substances. Combustion, oxidation, decomposition, etc.

27. Physical Changes Physical Change- alters a substance without changing its composition Key Terms: 1. Boil 2. Freeze 3. Dissolve 4. Melt 5. Condense 6. Break 7. Split 8. Crack 9. Crush 10. Cutting

28. © 2009, Prentice- Hall, Inc. Chemical Reactions In the course of a chemical reaction, the reacting substances are converted to new substances.

29. Chemical Reactions One or more substances changing into a new substance Starting Substance- Reactant New Substance- Product Iron + Sulfur  Iron Sulfide

30. How do you know? 6 Ways to Tell I. Color Change II. Energy absorbed or released (temp change) III. Gas or Solid Produced IV. Odor V. Precipitate (ppt)- solid that separates from solution VI. Not easily reversed

31. © 2009, Prentice- Hall, Inc. States of Matter

32. Solid- matter that has a definite shape and volume Liquid- matter that flows and has a fixed volume Gas- matter that takes up both the shape and volume of a container Vapor- a substance that is currently a gas but normally is a liquid or solid at room temperature. Plasma- matter consisting of a gaseous mixture of electrons and positive ions. Not found on Earth

33. States of Matter Solid Liquid Gas Definite Volume? YES NO Definite Shape? YES NO Temp. increase Small Expans. Large Expans. Com- pressible? NO YES

34. Matter Chart Properties:SolidLiquidGas or Vapor MassDefinite ShapeRigidIndefinite VolumeDefinite Indefinite Temp. Increase Small Expansion Moderate Expansion Large Expansion Com- Pressible? No Yes

35. Solid Liquid Gas Melt Evaporate Condense Freeze

37. Mixtures Mixture- Physical blend of two or more substances Mixture has variable composition Two Types of Mixtures  Heterogeneous- not uniform in composition  Homogeneous- completely uniform in compostion

38. Example Heterogeneous I. Blood II. Chocolate Chip Cookie III. Soil IV. Blood V. Mixed Salad Homogeneous I. Air II. Brass III. Black Coffee IV. Motor Oil V. Water

39. Solutions Homogeneous Mixture Mixed molecule by molecule Example: Sugar in Water (same composition as any other portion) Can occur between any state of matter

40. Common Solutions  Gas in Gas- O 2 in N (air)  Liquid in Gas- Water Vapor  Gas in Liquid- CO 2 in Water (soda water)  Liquid in Liquid- Acetic Acid in Water (vinegar)  Solid in Liquid- Kool Aid  Solid in Solid- Copper in Silver (sterling silver)

41. Solutions Like all mixtures, they keep the properties of the components Can by separated by physical means Not easily separated- can be separated

43. © 2009, Prentice- Hall, Inc. Separation of Mixtures

44. © 2009, Prentice- Hall, Inc. Distillation Distillation uses differences in the boiling points of substances to separate a homogeneous mixture into its components.

45. © 2009, Prentice- Hall, Inc. Filtration In filtration solid substances are separated from liquids and solutions.

46. © 2009, Prentice- Hall, Inc. Chromatography This technique separates substances on the basis of differences in solubility in a solvent.

47. Separating mixtures Only a physical change- no new matter Filtration- separate solids from liquids with a barrier Distillation- separate because of different boiling points Heat mixture Catch vapor in cooled area Chromatography- Chromatography- different substances are attracted to paper or gel, so move at different speeds

48. The Metric System

49. Measuring The numbers are only half of a measurement. It is 10 long. 10 what? Numbers without units are meaningless. How many feet in a yard? A mile? A rod?

50. The Metric System Easier to use because it is a decimal system. Every conversion is by some power of 10. A metric unit has two parts. A prefix and a base unit. prefix tells you how many times to divide or multiply by 10.

51. Base Units Length - meter - more than a yard - m Mass - grams - about a raisin - g Time - second - s Temperature - Kelvin or ºCelsius K or ºC Energy - Joules- J Volume - Liter - half of a two liter bottle- L Amount of substance - mole - mol

52. Prefixes giga- G 1,000,000,00010 9 mega - M 1,000,00010 6 kilo - k 1,00010 3 deci-d0.1 10 -1 centi-c0.01 10 -2 milli-m0.001 10 -3 micro-  0.000001 10 -6 nano-n0.000000001 10 -9

53. Volume calculated by multiplying L x W x H Liter the volume of a cube 1 dm (10 cm) on a side 1L = 1 dm 3 so 1 L = 10 cm x 10 cm x 10 cm 1 L = 1000 cm 3 1/1000 L = 1 cm 3 1 mL = 1 cm 3

54. Conservation of Mass Law of Conservation of Mass- in a physical or chemical reaction, mass is neither created nor destroyed; it is conserved. All mass can be accounted for. Mass of the Reactants = Mass of Products

55. Mass and Weight Mass is measure of resistance to change in motion Weight is force of gravity. Sometimes used interchangeably Mass can’t change, weight can

56. Mass Weight is a force. Mass is the amount of matter. 1 gram is defined as the mass of 1 cm 3 of water at 4 ºC. 1000 g = 1000 cm 3 of water 1 kg = 1 L of water 1 kg = 2.5 lbs

57. Converting khDdcm how far you have to move on this chart, tells you how far, and which direction to move the decimal place. The box is the base unit, meters, Liters, grams, etc.

58. Conversions convert 25 mg to grams convert 0.45 km to mm convert 35 mL to liters It works because the math works, we are dividing or multiplying by 10 the correct number of times. khDdcm

59. Uncertainty Basis for significant figures All measurements are uncertain to some degree Precision- how repeatable Accuracy- how correct - closeness to true value. Random error - equal chance of being high or low- addressed by averaging measurements - expected

60. © 2009, Prentice- Hall, Inc. Accuracy versus Precision Accuracy refers to the proximity of a measurement to the true value of a quantity. Precision refers to the proximity of several measurements to each other.

61. Uncertainty Systematic error- same direction each time Want to avoid this Bad equipment or bad technique. Better precision implies better accuracy You can have precision without accuracy You can’t have accuracy without precision (unless you’re really lucky).

62. Dimensional Analysis Using the units to solve problems

63. Dimensional Analysis Use conversion factors to change the units Conversion factors = 1 1 foot = 12 inches (equivalence statement) 12 in = 1 = 1 ft. 1 ft. 12 in 2 conversion factors multiply by the one that will give you the correct units in your answer.

64. Examples 11 yards = 2 rod 40 rods = 1 furlong 8 furlongs = 1 mile The Kentucky Derby race is 1.25 miles. How long is the race in rods, furlongs, meters, and kilometers? A marathon race is 26 miles, 385 yards. What is this distance in rods and kilometers?

65. Examples Science fiction often uses nautical analogies to describe space travel. If the starship U.S.S. Enterprise is traveling at warp factor 1.71, what is its speed in knots? Warp 1.71 = 5.00 times the speed of light speed of light = 3.00 x 10 8 m/s 1 knot = 2000 yd/h exactly

66. Because you never learned dimensional analysis, you have been working at a fast food restaurant for the past 35 years wrapping hamburgers. Each hour you wrap 184 hamburgers. You work 8 hours per day. You work 5 days a week. you get paid every 2 weeks with a salary of $840.34. How many hamburgers will you have to wrap to make your first one million dollars? Examples

67. A senior was applying to college and wondered how many applications she needed to send. Her counselor explained that with the excellent grade she received in chemistry she would probably be accepted to one school out of every three to which she applied. She immediately realized that for each application she would have to write 3 essays, and each essay would require 2 hours work. Of course writing essays is no simple matter. For each hour of serious essay writing, she would need to expend 500 calories which she could derive from her mother's apple pies. Every three times she cleaned her bedroom, her mother would made her an apple pie. How many times would she have to clean her room in order to gain acceptance to 10 colleges?

68. Units to a Power How many m 3 is 1500 cm 3 ? 3 1500 cm 3 1 m 100 cm 1 m 100 cm 1 m 100 cm 3 1500 cm 3 1 m 100 cm 3

69. Units to a Power How many cm 2 is 15 m 2 ? 36 cm 3 is how many mm 3 ?

70. Multiple units The speed limit is 65 mi/hr. What is this in m/s? 1 mile = 1760 yds 1 meter = 1.094 yds 65 mi hr 1760 yd 1 mi1.094 yd 1 m1 hr 60 min 1 min 60 s

71. Multiple units Lead has a density of 11.4 g/cm 3. What is this in pounds per quart? 454 g = 1 lb 1 L = 1.094 qt

72. Temperature and Density

73. Density How heavy something is for its size. The ratio of mass to volume for a substance. D = M / V Independent of how much of it you have gold - high density air low density.

74. Density Ratio of mass to volume D = m/V Useful for identifying a compound Useful for predicting weight An intrinsic property- does depend on what the material is

75. Calculating The formula tells you how. Units will be g/mL or g/cm 3 A piece of wood has a mass of 11.2 g and a volume of 23 mL what is the density? A piece of wood has a density of 0.93 g/mL and a volume of 23 mL what is the mass?

76. Density Problem An empty container weighs 121.3 g. Filled with carbon tetrachloride (density 1.53 g/cm 3 ) the container weighs 283.2 g. What is the volume of the container?

77. Density Problem A 55.0 gal drum weighs 75.0 lbs. when empty. What will the total mass be when filled with ethanol? density 0.789 g/cm 3 1 gal = 3.78 L 1 lb = 454 g

78. Floating Lower density floats on higher density. Ice is less dense than water. Most wood is less dense than water. Helium is less dense than air. A ship is less dense than water.

79. Density of water 1 g of water is 1 mL of water. density of water is 1 g/mL at 4ºC otherwise it is less

80. Temperature A measure of the average kinetic energy Different temperature scales, all are talking about the same height of mercury. Derive a equation for converting ºF toºC

81. Measuring Temperature Celsius scale. water freezes at 0ºC water boils at 100ºC body temperature 37ºC room temperature 20 - 25ºC 0ºC

82. 32ºF 0ºC = 32ºF

83. 100ºC212ºF 100ºC = 212ºF 0ºC = 32ºF 0ºC 32ºF

84. 100ºC212ºF 0ºC 32ºF 100ºC = 212ºF 0ºC = 32ºF 100ºC = 180ºF How much it changes

85. 100ºC212ºF 0ºC 32ºF 100ºC = 212ºF 0ºC = 32ºF 100ºC = 180ºF 1ºC = (180/100)ºF 1ºC = 9/5ºF How much it changes

86. ºC ºF 9 5 0ºC is not 0ºF

87. ºC ºF (0,32)= (C 1,F 1 )

88. ºC ºF (0,32) = (C 1,F 1 ) (100,212) = (C 2,F 2 )

89. Measuring Temperature Kelvin starts at absolute zero (-273 º C) degrees are the same size C = K -273 K = C + 273 Kelvin is always bigger. Kelvin can never be negative. 273 K

90. Temperature is different from heat. Temperature is which way heat will flow. (from hot to cold) Heat is energy, ability to do work. A drop of boiling water hurts, kilogram of boiling water kills.

91. Units of heat are calories or Joules 1 calorie is the amount of heat needed to raise the temperature of 1 gram of water by 1ºC. A food Calorie is really a kilocalorie. How much energy is absorbed to heat 15 grams of water by 25ºC. 1 calorie = 4.18 J

92. Elements & Compounds Element- simplest form of matter I. Elements can’t be separated II. Elements are the building block III. Smallest part is an atom

93. Compounds Compound- formed by 2 or more elements I. Substances that can be separated into simpler substances only by chemical reactions II. When broken down, the pieces have completely different properties than the compound III. Pure substances IV. Represented by a formula V. Smallest part is a molecule

94. Compound or Mixture CompoundMixture One kind of piece- Molecules More than one kind - Molecule or atoms Making is a chemical change Making is a physical change Only one kindVariable composition

95. What is it? Element, Compound or Mixture 1. Silver 2. Orange Juice 3. Ice Tea 4. Potassium Chloride 5. Oxygen 6. Air 7. Pine Tree

96. Which is it? Element Compound Mixture