Matter and Properties of Matter (Lecture Notes)

Vocabulary-style flashcards covering matter, its properties, states, changes, and mixtures.

Matter

Anything that has mass and takes up space (volume).

Mass

The amount of matter in an object; measured in grams.

Volume

The amount of space an object occupies; measured in liters or cubic centimeters (mL for liquids).

Density

Mass per unit volume; D = m/v; how tightly matter is packed.

State of matter

Forms matter can take: solid, liquid, gas, and plasma.

Solid

A state with definite shape and volume; particles are tightly packed and vibrate in place.

Liquid

A state with definite volume but no definite shape; particles can flow past one another.

Gas

A state with no definite shape or volume; particles are widely spaced and move freely.

Plasma

A high-energy state of matter with charged particles; examples include lightning and flames.

Intermolecular forces

Attractive and repulsive forces between molecules that influence state and properties.

Temperature

A measure of the average kinetic energy of particles in a substance.

Kinetic energy

Energy of motion of particles; increases with temperature.

Phase change

A physical change from one state of matter to another (melting, freezing, evaporation, condensation, sublimation, deposition) without changing the substance’s identity.

Melting

Solid to liquid; occurs at the melting point.

Freezing

Liquid to solid; occurs at the freezing point.

Evaporation

Liquid to gas; surface-changing vaporization (not necessarily at boiling point).

Boiling

Vaporization that occurs throughout a liquid at its boiling point.

Condensation

Gas to liquid.

Sublimation

Solid to gas.

Deposition

Gas to solid.

Physical property

A characteristic observed or measured without changing the substance’s identity (color, density, conductivity, etc.).

Chemical property

A substance’s ability to undergo a chemical change (e.g., flammability, reactivity).

Conductivity

The ability of a material to conduct heat or electricity.

Flammability

The ability of a substance to catch fire.

Reactivity

How readily a substance chemically interacts with other substances.

Physical change

A change in size, shape, or state of matter without changing the substance’s identity (melting, freezing, etc.).

Chemical change

A process where one or more substances are transformed into new substances.

Evidence of chemical change

Signs such as heat, light, sound, color change, gas evolution, or odor.

Pure substance

Matter with a fixed composition and definite properties; either an element or a compound.

Element

A substance made of one type of atom.

Compound

A substance made of two or more elements chemically bonded; has a definite composition.

Mixture

A combination of two or more substances that maintain their identities.

Homogeneous mixture

A mixture with uniform composition throughout (solutions like Kool-Aid, saltwater).

Heterogeneous mixture

A mixture with nonuniform composition (pizza, salad).

Solute

The substance dissolved in a solution.

Solvent

The component that dissolves the solute; the dissolving medium.