1. Chemistry Notes

2. Study of matter and its properties
What is chemistry?
Study of matter and its properties

3. Why study chemistry?
Used in career fields like doctor, nurse, pharmacist, engineer, rocket scientist, etc
Can help you stay healthier – helps explain reactions in your body and certain diseases and their treatments

4. Matter’ definition
It has to have 2 things
Has to have mass and volume

5. How to describe matter?
Physical Properties - properties you can test for or sense without changing the substance
Examples:
density color taste
pH magnetism boiling point
melting point odor

6. Chemical properties
Chemical properties – property in which you test how it reacts with another substance, and the substance being tested is changed
Reaction with baking soda
Flammability
Decompose with heat

7. State of Matter and Their Properties
All matter can exist as a gas, solid, or liquid at the proper temperature and pressure

8. Solid Particles are close to one another and don’t move Fixed shape
Doesn’t fill container necessarily
High density
Not very compressible
Examples: steel, copper, plastic, ice

9. Gases Particles are far apart and moving fast Always fills container
Takes shape of container
Least density
Compressible
Examples: air, natural gas, water vapor

10. Liquid Particles can move past each other Can fill a container
Takes shape of a container
Medium density
Slightly compressible
Examples: liquid water, milk

11. Two major classifications Two major classifications
Pure substance
Mixture

12. Two kinds of pure substances
Element
Definition – pure substance that can’t be broken down into simpler substances by chemical or physical means
 #’s – approximately 118
The substances on the periodic table
Examples: gold, iron, hydrogen, oxygen

13. Compound
Definition – pure substance made up of two or more different elements chemically combined
#’s – millions
Examples: salt, water, sugar

14. Mixture Mixture – two or more pure substances physically combined
Gaseous mixtures – like air
Solid mixtures – like alloys such as brass and stainless steel
Liquid mixtures – milk, salt water
Mixtures with more than one phase
Carbonated beverages

15. Separating or purifying matter
Mixtures – can be separated by physical means
Separate a mixture of any two pure liquids
Distillation
Separate the water in salt water from the salts
Boil off the water and salts will remain
Separate a mixture of gases
Cool them – they will condense at different temperatures

16. Compounds Can only be separated by chemical means
Decomposition – Heat to high temperature:
Ex. copper oxide ore from the earth – drive off
the oxygen by heating to a high temperature
Electrolysis
Pure water can be separated into hydrogen and oxygen gases by using an electric current

17. Elements
Can’t be purified any further or broken apart by chemical or physical means

18. Chemical Changes
Definition – change in which a substance changes its chemical identity
Examples
Burning propane
Reaction between vinegar and baking soda
Also called a chemical reaction

19. Physical changes
Definition – change in which a substance changes its physical properties without changing its identity.
  Examples
Cutting wood
Tearing up a piece of paper
Melting ice
Boiling water