Chemistry key terms

The quantitative relationship between the amounts of reactants and products in a balanced chemical equation.

The ability of a material to withstand forces without breaking or permanently changing shape.

An acid that is completely ionised in aqueous solution.

A soluble base that dissociates completely in water to produce hydroxide ions, $\text{OH}^-(aq)$.

A way of grouping substances according to the particles present, their arrangement and the bonding or forces between them.

A shortened representation that shows the order in which atoms or groups are connected, such as $CH_3CH_2OH$.

A drawing or model used to show selected features of a chemical structure.

A particle smaller than an atom that forms part of its structure, such as a proton, neutron or electron.

The variable written alone on one side of a formula and calculated from the other variables.

The variable written alone on one side of an equation; changing the subject means rearranging the equation to isolate a different variable.

A direct change from solid to gas without becoming liquid.

A small number within a chemical formula that shows how many atoms of the preceding element are present in one molecule or formula unit.

Replacing variables with known numerical values.

The substance on which an enzyme acts.

A collision between reacting particles that results in a chemical reaction.

A word ending added to the main part of a word; in chemical names, endings such as -ide and -ate provide information about composition.

A type of carbohydrate molecule; sugar molecules form the units on which starch is based.

A negatively charged ion with the formula $\mathrm{SO_4^{2-}}$.

A pollutant gas with the formula SO₂, produced when sulfur reacts with oxygen.

A number written at the upper right of an ion's formula to show the size and sign of its electrical charge.

The total area of a solid exposed to its surroundings.

The surface area of an object divided by its volume; it measures how much surface is exposed relative to the amount of material present.

Everything outside the reaction system that can exchange energy with it.

Using resources in a way that considers present benefits and the resources available for the future.

Using natural resources at a rate that allows them to be replaced, so their use can continue into the future.

Development that meets the needs of current generations without compromising the ability of future generations to meet their own needs.

A representation of a chemical reaction using the formulae of its reactants and products.

An organic compound produced deliberately through chemical reactions; it may be identical to a compound that also occurs naturally.

A manufactured material or product made by chemical processes rather than obtained directly in its final form from nature.

The substances and apparatus chosen for study in an investigation.