1. Honors Chemistry Mr. Roberts
Highlights of Chapter 1
Honors Chemistry
Mr. Roberts

2. What is Chemistry?
Chemistry is the study of matter and the changes it undergoes.
What is matter?
Atom, elements and compounds, etc…
States of matter.
Describe the particle arrangement of solids, liquids and gasses.
The Scientific Method: systematic approach to problem solving

3. Pure Substances vs. Mixtures
Homogeneous mixtures are called solutions
Building blocks of matter
To separate a compound involves a chemical change

4. Elements Compounds Mixtures Atoms
Molecules (two or more different types of atoms), formula units…chemically combined
Compounds
Can be composed of elements and compounds, compounds and compounds, elements and elements, etc…physically combined
Mixtures

5. Law of Constant Composition
Also know of the law of definite proportions
If oxygen has a mass of 16g and hydrogen has a mass of 1 g in a 100g sample of water, H2O, oxygen would contribute 89% of the mass whereas hydrogen would contribute 11% of the mass. Regardless of the sample size (i.e. 50 g sample of water the ratio of hydrogen to oxygen would remain the same giving the compound of water a constant composition.

6. Mixtures (can be separate into components through physical means)
Homogeneous
Heterogeneous
Uniformly mixed at a molecular level
Only has one phase
Called a Solution
Ex: black coffee, salt water, tap water, etc…
Not uniformly mixed
Contains more than one phase (separations)
Ex: Italian salad dressing, cereal and milk, oil and vinegar, etc…
1 phase
2 phases

7. Properties of Matter Physical Properties: Chemical Properties:
Can be observed without changing a substance into another substance.
Boiling point, density, mass, volume, etc.
Chemical Properties:
Can only be observed when a substance is changed into another substance.
Flammability, corrosiveness, reactivity with acid, etc.

8. How can you separate a mixture?
Filtration
Decanting
Freezing
Distillation
Other means are possible…magnetism for example.

9. Physical/Chemical Change
Physical change changes the physical appearance of the starting substance(s).
Chemical change changes the composition of starting substance(s).