Chapter 1
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Transcript of Chapter 1
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