Edexcel IGCSE Chemistry - States of Matter Vocabulary Flashcards

Vocabulary flashcards covering key terms and definitions from the notes on states of matter, diffusion, and solubility.

States of matter

The three physical forms—solid, liquid, and gas—differ in particle energy, arrangement, and movement.

Solid

Least energy; particles vibrate in fixed, regular, very close arrangement.

Liquid

More energy than a solid but less than a gas; particles are closer together with a random arrangement.

Gas

Most energy; particles are spread apart and arranged randomly.

Melting

Solid changes to liquid at the melting point; energy increases and particles move more.

Freezing

Liquid changes to solid at the melting point; energy decreases and particles become more regularly arranged.

Boiling

Liquid changes to gas at the boiling point; energy increases and particles move freely and spread apart.

Condensing

Gas changes to liquid at the boiling point; energy decreases and particles move slower and come together.

Physical change

A non-chemical change involving forces between particles; no new substance is formed.

Melting point

Temperature at which a solid melts into a liquid.

Boiling point

Temperature at which a liquid boils and becomes a gas (also where condensation can occur).

Solvent

The liquid in which a solute dissolves.

Solute

Substance that dissolves in a solvent to form a solution.

Solution

A mixture formed when a solute dissolves in a solvent.

Saturated solution

A solution in which no more solute can dissolve at a given temperature.

Solubility

Grams of solute that will dissolve in 100 g of solvent at a specific temperature.

Solubility curve

A graph of solubility versus temperature (and pressure for gases); solids usually become more soluble with higher temperature, gases with higher pressure; identifies unsaturated, saturated, and supersaturated states.

Unsaturated

Mass of solute below the solubility curve—more solute can still dissolve.

Supersaturated

Mass of solute above the solubility curve—more solute is dissolved than normally possible and is unstable.

Diffusion

Movement of particles from high concentration to low concentration; does not occur in solids because particles cannot move.

Dilution

Process of adding solvent (e.g., water) to a solution to decrease its concentration.

Gas solubility (solubility increases with pressure)

For gases, solubility in a liquid increases as pressure increases.