Chemistry Definitions

Matter

Anything that has mass and occupies space

Mass

a measurement of the amount of matter in an object

Physical properties of matter

Can be observed or measured without attempting to change the composition of the matter being observed

Examples of physical properties of matter

Color, shape, and mass

Chemical properties of matter

can be observed or measured only by attempting to change the matter into new substances

Physical changes of matter

take place without a change in composition

Examples of physical changes in matter

freezing, melting, or evaporation of a substance

Chemical changes of matter

always accompanies by a change in composition

Molecules

smallest particle of a pure substance

Atoms

particles that make up Molecules

Homoatomic molecules

contain the same kind of atoms

Heteroatomic molecules

contain two or more kinds of atoms

Pure substance

have a constant composition and fixed set of physical and chemical properties

Mixtures

can vary in composition and properties (solutions)

Elements

pure substances that are made up of homoatomic molecules or individual atoms of the same kind (O2)

Compounds

pure substances that are made up of heteroatomic molecules or individual atoms of two or more different kinds (H2O)

Mega (M)

1,000,000

Kilo (k)

1,000

deci (d)

.1

Centi

.01

Milli

.001

Boiling point in water C° and F°

100°C and 212°F

Freezing point in water C° and F°

0°C and 32°F

Metric untis for length

meter, centimeter, milimeter, klilometer

Metric untis for volume

liter and milliliter

Metric units for mass

gram, milligram, kilogram

3 subatomic particles

protons, neutrons, and electrons

Where are protons and neutrons bound together

in the nucleus

isotopes have

same number of protons but different number of neutrons