Year 8 Chemistry Revision Flashcards

This set covers Year 8 Chemistry fundamentals including elements, compounds, mixtures, atomic structure, physical and chemical changes, states of matter, and chemical formulas based on the revision guide.

What is the definition of an element?

A pure substance made of only one type of atom.

What is a compound?

A substance made when two or more different elements chemically join together.

What is a mixture?

Two or more substances physically combined, not chemically joined.

Provide examples of mixtures listed in the transcript.

Air, salt water, and trail mix.

What are the charge and location of a Proton?

Charge: $+$; Location: Nucleus.

What are the charge and location of a Neutron?

Charge: $0$; Location: Nucleus.

What are the charge and location of an Electron?

Charge: $-$; Location: Electron shells.

What characterizes a physical change?

A change in the state, shape, or appearance without making a new substance; these are often reversible.

What characterizes a chemical change?

The production of one or more new substances; these are often difficult to reverse.

Name four examples of chemical changes provided in the notes.

Burning, rusting, cooking an egg, and vinegar reacting with baking soda.

Describe the particle arrangement and movement in a solid.

Particles are close together and vibrate in place; it has a fixed shape and volume.

Describe the particle arrangement and movement in a gas.

Particles are far apart and move quickly; it has no fixed shape or volume.

What is the name for the state change from a solid directly to a gas?

Sublimation.

What are the six possible signs of a chemical change?

Gas being produced, temperature change, colour change, light being produced, a new smell, or a solid forming from liquids.

What happens to atoms during a chemical reaction?

Atoms are rearranged to make new substances; they are not destroyed.

What are the common properties of metals?

Generally shiny, strong, good conductors of heat and electricity, and often malleable and ductile.

What are the common properties of non-metals?

Generally poor conductors of heat and electricity and often brittle when solid.

Define reactants and products in a chemical equation.

Reactants are the substances you start with; products are the new substances produced.

What is the chemical symbol for Sodium?

$$Na$$

What is the chemical symbol for Iron?

$$Fe$$

What does the subscript number in a chemical formula like $H_2O$ indicate?

It tells you how many atoms of that element are in one molecule.

In the formula $CO_2$, how many oxygen atoms are there?

$2$ oxygen atoms.

What does the prefix $2$ in $2H_2O$ represent?

It means there are two water molecules.

Is rusting iron a physical or chemical change?

Chemical change.

Is melting ice a physical or chemical change?

Physical change.