Year 7 Chemistry Review Flashcards

Flashcards based on Chemistry Year 7 lecture notes to help students review for their exam.

What happens to gas particles in a flask when heated?

They start to move faster and take up more space, causing the balloon to inflate.

List the three states of matter.

Solid, liquid, and gas.

Define 'change of state'.

A physical change in matter when it absorbs or loses energy, like from a liquid to a gas.

What is the boiling point?

The temperature at which a liquid boils and becomes a gas.

What is the melting point?

The temperature at which a solid melts and becomes a liquid.

What is condensation?

The cooling down of a gas into a liquid.

What is solidification?

The cooling down of a liquid into a solid.

Define matter.

Anything that has space and volume; matter is made up of atoms.

What are three major states of matter?

Solid, liquid, and gas.

Define evaporation.

A change in state from liquid to gas.

What is physical property?

A property of a substance that can be measured or observed without changing the substance into something else; examples are color and boiling point.

What is chemical property?

How a substance behaves in a chemical reaction, such as how it reacts with an acid.

List properties of particles.

Are too small to be seen, are always moving, have mass, can combine, have spaces between them, and have forces holding them together.

Define mass.

The amount of matter in a substance, usually measured by weight; the mass of an object never changes even in space.

Define atom.

The smallest particle of matter.

Define molecule.

A group of two or more atoms bonded together, such as a water molecule.

Define chemistry.

The branch of science that deals with matter and the changes that take place within it.

What is the particle model?

Explains the movement and arrangement of particles in matter; particles always have kinetic energy.

What is kinetic energy?

The energy possessed by moving objects.

Define diffusion.

The movement of particles from a high concentration to a low concentration.

In which state of matter does diffusion occur fastest and why?

Gases because the particles are moving freely and quickly, and there is plenty of space between them.

Define hardness (in the context of minerals).

How easily a mineral can be scratched.

Define tensile strength.

A measure of the flexibility of the links or bonds between the particles.

Define compression strength.

A measure of how much force a substance can withstand without being crushed.

Define viscosity.

A measure of how slowly a liquid changes its shape; the thickness of a liquid.

Define density.

A measure of the mass per unit of volume; describes the number of particles and how tightly packed they are.

What is the formula for Density?

Density = Mass/Volume

Define mixture.

A combination of two or more pure substances.

Define pure substance.

Something that contains only one type of substance (e.g. a single element or a single compound).

Define suspensions.

A cloudy liquid containing insoluble particles that might settle to the bottom of the container.

Define sediment.

Substance of matter that settles to the bottom in a mixture

Define colloids.

Suspensions that do not separate easily; a mixture that always looks cloudy because clumps of insoluble particles remain suspended throughout it.

Define emulsions.

A colloid of two or more liquids where one is suspended in the other as tiny droplets.

Define solution.

A mixture of a solute dissolved in a solvent; usually transparent.

Define solute.

Substance dissolving.

Define solvent.

Liquid solute dissolves into.

Define soluble.

A substance that is able to dissolve in a liquid.

Define insoluble.

A substance that cannot dissolve.

Describe dilute solution.

Containing a small number of solute particles in the volume of solution.

Describe concentrated solution.

Containing a large number of solute particles in the volume of solution.

Describe saturated solution.

A solution in which no more solute can be dissolved.

Define decanting.

A technique used to separate sediment from the liquid it is in by carefully pouring the liquid away.

Define sedimentation.

The process of a substance settling to the bottom in a mixture.

Define flotation.

The action of floating in a liquid or gas.

Define flocculants.

A chemical added to a mixture to make suspended particles clump together.

Define sieving.

A separation technique based on the difference in particle size.

Define filtering.

A technique used to separate different-sized particles in a mixture depending on the size of the holes in the filter used.

Define residue (in the context of filtering).

What is left in the filter paper as it cannot pass through, usually a solid substance.

Define filtrate (in the context of filtering).

What passes through the filter paper, usually a liquid.

Define centrifuging.

A technique used to separate light and heavy particles by rapidly spinning the mixture.

Define evaporation.

A change in state from liquid to gas; also a technique used to separate dissolved solids from water.

Define crystallisation.

A separation technique used with evaporation to remove a dissolved solid from a liquid; after the liquid has been evaporated the solid remains, often in the form of small crystals.

Define distillation.

A technique that uses evaporation and condensation to separate a solid from the solvent in which it has dissolved; can also separate two liquids with different boiling points.

Define solubility.

How easily a substance dissolves in a solvent.

Define chromatography.

A technique used to separate substances according to their differing solubilities.