1. Scientific method

a. Make observations

b. Formulate hypotheses

c. Perform experiments

2. Models (theories) are explanations of why nature behaves in a particular way

a. They are subject to modification over time and sometimes fail.

3. Quantitative observations are called measurements

a. Consist of a number and a unit

b. Involve some uncertainty

c. Uncertainty is indicated by using significant figures

i. Rules to determine significant figures

1. Nonzero integers. Nonzero integers always count as significant figures.

2. Zeros. There are three classes of zeros:

a. Leading zeros – the zeros the precede all the nonzero digits do not count

b. Captive zeros – the zeros between nonzero digits always count

c. Trailing zeros – the zeros at the right end of the number are only significant if the number contains a decimal point

3. Exact numbers – are assumed to have an infinite amount of significant figures ii. Calculations using significant figures

1. For multiplication or division, the number of sig figs in the result is the same as the number in the least precise measurement used in the calculation.

a.

2. For addition or subtraction, the result has the same number of decimal places as the least precise measurement used in the calculation.

a.

d. Preferred system is SI

4. Temperature Conversions

a.

b.

c.

5. Density

a.

6. Matter can exist in three states:

a. Solid

b. Liquid

c. Gas

7. Two classifications of mixtures

a. Homogeneous – having visibly