1. Chapter 1 Introduction to Chemistry

2. What you’ll learn…
You will describe the relationships between chemistry and matter
You will recognize how scientific methods can be used to solve problems
You will distinguish between scientific research and technology

3. Chemistry and Matter
Chemistry is the study of matter and the changes that it undergoes
Matter is anything that has a mass and takes up space
Mass is a measurement that reflects the amount of matter
Is air matter?

4. Weight is a measurement not only of the amount of matter but also the effect of the Earth’s gravitational pull on that matter
Why would scientists use “mass” instead of “weight”?

5. Macroscopic vs. Microscopic
Macroscopic matter does not need a microscope to see it whereas microscopic matter needs a microscope
Submicroscopic= atoms
FYI: 1 million million atoms could fit onto the period at the end of a sentence

6. Scientific Methods Observations
Qualitative Data- information that describes
Examples: color, odor, shape
Quantitative Data- numerical information
Examples: how tall, how fast, how much

7. Experiments
Independent variable- variable that you plan to change
Dependent variable- variable that changes in response to a change in the independent variable

8. Chapter 3 Matter- Properties and Changes
What about Chapter 2???
(We’ll come back to that…)

9. Pure Substance
Substance- matter that has a uniform and unchanging composition
Examples: Table Salt, water, sugar

10. Physical Properties of Matter
A physical property can be observed or measured without changing the sample’s composition
Examples: Density, Color, Odor, Taste, Hardness, Melting Point, Boiling Point

11. Extensive vs. Intensive Properties
Extensive Properties are dependent upon the amount of substance present
Example: Mass
Intensive Properties are independent of the amount of substance present
Example: Density, Color

12. Chemical Properties of Matter
Chemical property -the ability of a substance to combine with or change into one or more other substances
Example: The ability of iron to form rust when combined with oxygen

13. States of Matter Solid Liquid Gas Definite shape Definite volume Flows
Constant volume
Takes the shape of its container
Gas
Flows to conform to the shape of its container
Fills entire volume of container
Vapor- refers to the gaseous state of a substance that is a solid or a liquid at room temperature

14. Physical Change
Physical changes alter a substance without changing its composition
Example: cutting a sheet of paper
Indicating words: bend, grind, crush, split, melting, freezing, condense

15. Chemical Changes AKA Chemical Reaction
A process that involves one or more substances changing into new substances

16. Conservation of Mass
The law of conservation of mass states that matter is neither created nor destroyed (it is conserved)
WOOD + OXYGEN  ASH WATER VAPOR + CARBON DIOXIDE

17. Chemical or Physical Change?
wind eroding rocks _________________________
dead leaves decaying __________________________
rain puddle drying up __________________________
mixing flour and baking powder__________________________
gasoline evaporating __________________________
hydrogen peroxide decomposing__________________________
bread baking in an oven __________________________
instant tea dissolving in water __________________________
milk souring __________________________
gasoline burning __________________________

18. ANSWERS wind eroding rocks – PHYSICAL CHANGE
dead leaves decaying – CHEMICAL CHANGE
rain puddle drying up – PHYSICAL CHANGE
mixing flour and baking powder- PHYSICAL CHANGE
gasoline evaporating – PHYSICAL CHANGE
hydrogen peroxide decomposing- CHEMICAL CHANGE
bread baking in an oven – CHEMICAL CHANGE
instant tea dissolving in water – PHYSICAL CHANGE
milk souring – CHEMICAL CHANGE
gasoline burning- CHEMICAL CHANGE

19. Mixtures
A mixture is a combination of two or more substances in which each pure substance retains its individual chemical properties

20. Heterogeneous Mixture- one that does not blend smoothly throughout and which the individual substances remain distinct
Examples: Sand and Water, Oil and Water, Cement
Homogeneous Mixture (Solutions)- has constant composition throughout; it always has a single phase
Examples: salt water, vinegar, alloys

21. Separating Mixtures
Filtration- technique that uses a porous barrier to separate a solid from a liquid
Distillation- technique that is based on differences in the boiling points of substances
Crystallization- technique that results in the formation of pure solid particles of a substance from a solution containing the dissolved substance
Chromatography- separates the components of a mixture on the basis of the tendency of each to travel or be drawn across the surface of another material

22. Elements and Compounds
Element- a pure substance that cannot be separated into simpler substances
Located on the periodic table in rows and periods
Periods= Horizontal Rows
Groups= Vertical Columns
Compound- a combination of two or more different elements that are combined chemically

23. Law of Definite Proportions
Elements comprising compounds combine in definite proportions
Regardless of the amount, a compound is always composed of the same elements in the same proportion by mass
Percent by Mass- the ratio of the mass of each element to the total mass of the compound as a percentage

24. Practice Problem 15.9% Hydrogen
A 78.0g sample of an unknown compound contains 12.4 g of hydrogen. What is the percent by mass of hydrogen in the compound?
15.9% Hydrogen

25. Pure Substance or Mixture
Material
Pure Substance or Mixture
Element, Compound, Homogeneous, Heterogeneous
Limestone (CaCO3)
Soil
Bronze
Aluminum
Sugar + water
Concrete
Sterling Silver
Caffeine

26. ANSWERS Material Pure Substance or Mixture
Element, Compound, Homogeneous, Heterogeneous
Limestone (CaCO3)
PURE SUBSTANCE
COMPOUND
Soil
MIXTURE
HETEROGENOUS
Bronze
HOMOGENOUS
Aluminum
ELEMENT
Sugar + water
Concrete
Sterling Silver
HOMOGEN
Caffeine

27.  Homework  Page 9 Page 13 Page 60 Page 69 Page 76 Page 77 #6-8,10
#12
Page 60
#1-5
Page 69
#15-17
Page 76
#21-23
Page 77
#25-30 SKIP #28