Chapter 1

Introduction: Matter and Measurement

1

Properties of Matter

Physical property: a property that can be observed without changing the identity and composition of the substance

Chemical property: a property that describes the way a substance may react to form other substances

2

Properties of Matter

Intensive property: a property that depends on the identity of the substance

Extensive property: a property that depends on the amount of the substance

3

Changes in Matter

Physical change: a substance changes its physical appearance but not its composition

Chemical change: a substance is transformed in a chemically different substance

4

Units of Measurement

5

SI Units

6

Metric System

7

Temperature

The Celsius and Kelvin scales are those commonly used in science.

0 °C = 273 K

8

Derived Units

Volume and density are considered derived units because they are made up of SI units.

d = mV

9

Uncertainty in Measurements

10

Significant Figures

1) All nonzero digits are significant

2) All zeros in between nonzero digits are significant

3) Zero at the beginning of a number are never significant

74198 has 5 sig figs

3705 has 4 sig figs

0.0064 has 2 sig figs

11

Significant Figures

4) Zeros at the end of a number are only significant if there is a decimal in the number

5) Counted numbers and conversion factors have an unlimited number of sig figs

12

Significant Figures

When you add or subtract using sig figs, the answer has the same number of decimal places as the number with the least decimal places.

When you multiply or divide using sig figs, the answer has the same number of sig figs as the number with the least sig figs.

13

Accuracy and Precision

Accuracy: how close a measurement is to its correct value

Precision: how closely individual measurements agree with one another

14