Summary of lessons so far
- Summary of lessons so far
- Glossary of Words
Physical and Chemical Properties
All substances have distinct physical and chemical properties, and may undergo physical or chemical changes. Physical properties, such as hardness and boiling point, and physical changes, such as melting or freezing, do not involve a change in the composition of matter. Chemical properties, such flammability and acidity, and chemical changes, such as rusting, involve production of matter that differs from that present beforehand.
Measurable properties fall into one of two categories. Extensive properties depend on the amount of matter present, for example, the mass of gold. Intensive properties do not depend on the amount of matter present, for example, the density of gold. Heat is an example of an extensive property, and temperature is an example of an intensive property.
Measurements provide quantitative information that is critical in studying and practicing chemistry. Each measurement has an amount, a unit for comparison, and an uncertainty. Measurements can be represented in either decimal or scientific notation. Scientists primarily use the SI (International System) or metric systems.
We use base SI units such as meters, seconds, and kilograms, as well as derived units, such as liters (for volume) and g/cm3 (for density). In many cases, we find it convenient to use unit prefixes that yield fractional and multiple units, such as microseconds (10−6 seconds) and megahertz (106 hertz), respectively.
Glossary of Words
unit of temperature; water freezes at 0 °C and boils at 100 °C on this scale
change producing a different kind of matter from the original kind of matter
behavior that is related to the change of one kind of matter into another kind of matter
cubic centimeter (cm3 or cc)
volume of a cube with an edge length of exactly 1 cm
cubic meter (m3)
SI unit of volume
ratio of mass to volume for a substance or object
property of a substance that depends on the amount of the substance
property of a substance that is independent of the amount of the substance
SI unit of temperature; 273.15 K = 0 ºC
standard SI unit of mass; 1 kg = approximately 2.2 pounds
measure of one dimension of an object
(also, cubic decimeter) unit of volume; 1 L = 1,000 cm3
standard metric and SI unit of length; 1 m = approximately 1.094 yards
1/1,000 of a liter; equal to 1 cm3
change in the state or properties of matter that does not involve a change in its chemical composition
characteristic of matter that is not associated with any change in its chemical composition
SI unit of time
SI units (International System of Units)
standards fixed by international agreement in the International System of Units (Le Système International d’Unités)
standard of comparison for measurements
amount of space occupied by an object