1. Chapter 1

2. What is a chemical?
A chemical is any substance that has a definite composition.
Chemical changes and reactions take place all the time.

3. Examples of chemical reactions:
Photosynthesis –turns CO2 and sunlight into food and oxygen
Rusting of metal
Burning a match

4. objectives Distinguish between elements and compounds
Distinguish between pure substances and mixtures
Classify mixtures as homogeneous or heterogeneous
Explain the difference between mixtures and compounds

5. Classifying matter Everything around you is made up of ___________.
All matter is composed of ___________.

6. Pure substances
Every pure substance has characteristic __________ that can be used to identify it.
These properties can be ____________ or chemical.
There are two types of pure substances, ____________ and ____________.

7. Elements
Elements are pure substances that contain only one kind of atom.
Copper and bromine are elements.
The __________ __________ is an organized list of all the elements.

8. Molecules
A ____________ usually consists of two or more atoms combined in a definite ratio.
Examples H2 F2
Cl2

9. Compounds Pure substances that are not ____________ are compounds.
Compounds are composed of more than one kind of atom.

10. Classify the following as a Pure substance, compound, or element
Classify the following as a Pure substance, compound, or element. Choose all that apply
CO2 F2
C6H12O6
SO4
C9H8O4
H2O Fe Ag

11. Mixtures
A mixture is a sample of matter that contains two or more pure substances ___________ combined.
Most kinds of foods are mixtures except _________ and _________.
Air is a mixture
Water (is, is not) a mixture

12. Classifying mixtures
In homogeneous mixtures the pure substances that are combined are distributed uniformly throughout the entire mixture.
Gasoline
Syrup
Air
There different components cannot be seen

13. Continued…
In heterogeneous mixtures, the substances are not evenly mixed
Italian dressing
Chocolate chip cookies
Salad
Muddy water

14. Review What is the difference between an element and a compound?
What’s the difference between pure substances and mixtures?
What’s the difference between mixtures and compounds?