Year 7 Chemical Sciences: Particle Theory, Mixtures, and Separation Techniques

Vocabulary flashcards covering Year 7 Chemical Sciences essential terms, particle theory, states of matter, solutions, and separation techniques.

Filtration

A separation technique used for separating an insoluble substance from a liquid.

Filtrate

The liquid component that flows through into the flask during filtration.

Decantation

A separation technique for insoluble substances where a top liquid layer (like oil on top of water) can be poured off.

Evaporation

A process where the liquid solvent is turned into a gas, leaving the solid solute behind.

Chromatography

A separation process where a liquid moves up via capillary action, separating its components.

Crystallisation

A process by which a solid solute crystallises as the liquid solvent evaporates.

Distillation

A process where the liquid solvent is evaporated and then cooled back into a liquid.

Physical Change

A change that does not involve the creation of a new substance and is easily reversed (e.g., melting ice).

Chemical Change

A change that involves making a new substance and is not easily reversed (e.g., burning wood).

Solid

A state of matter that has a fixed shape and fixed volume, with fixed particles that are not liquid or fluid.

Liquid

A state of matter that flows freely and has a constant volume but takes the shape of its container (e.g., water or oil).

Gas

A state of matter in which particles expand freely to fill a container, having no fixed shape and no fixed volume.

Pure Substance

A substance made of only one type of particle or thing.

Mixture

A combination made up of two or more substances that can be physically separated.

Solution

Formed when a solid solute is dissolved in a liquid solvent (e.g., salt water).

Solvent

The liquid component of a solution (e.g., water).

Solute

The solid component that is dissolved in a solution (e.g., salt).

Suspension

A mixture containing large molecules or particles that sink to the bottom over time (e.g., sand and water).

Dissolve

To break down and incorporate a solid into a liquid so as to form a solution.

Soluble

Capable of being dissolved.

Insoluble

Not capable of being dissolved.

Concentrated

A solution containing a large amount of solute relative to solvent (e.g., $50\,\text{g}$ of salt in $500\,\text{mL}$ of water).

Dilute

A solution containing very little solute relative to solvent (e.g., $1\,\text{g}$ of salt in $500\,\text{mL}$ of water).

Saturation

A state where there is too much solute for the solvent to dissolve any further (e.g., $1\,\text{kg}$ of salt in $100\,\text{mL}$ of water).

Colloid

A mixture containing tiny particles that are evenly spread out but do not dissolve (e.g., milk; often cloudy).