Chemistry key terms

A weather event, such as a heatwave, drought or period of very heavy rainfall, that is unusually severe or uncommon for a particular place and time.

A multiplicative comparison found by dividing one value by another; for example, a factor of 2 means twice as large.

Rewriting an expression as a product, usually by taking out a common factor.

A tenfold change: the original value is multiplied or divided by 10.

Multiplication by 10; for example, a ten-fold increase changes 2 into 20.

A test in which only the independent variable is changed while relevant control variables are kept constant.

An incorrect positive result caused by something other than the ion being tested for.

A group of organic compounds with related structures and similar chemical properties.

A substance used as a starting material to make other chemicals and materials.

The breakdown of sugar by yeast without oxygen, producing ethanol and carbon dioxide.

A substance added to soil to supply nutrients that help plants grow.

The liquid that passes through filter paper during filtration.

The removal of insoluble solid particles by passing water through a filtering material.

Particles with diameters from 100 nm to 2500 nm; the upper limit is 2.5 micrometres.

A natural resource that is used much faster than it forms, so its supply can eventually run out.

A consistent, defined observation used to stop timing, such as the moment a cross is no longer visible.

Particles held in place within a coating or another material, so they are less likely to be released and enter the body or environment.

An instrumental method that analyses metal ions in a solution using the light emitted when the sample is placed in a flame.

An instrument that provides data which can be used to identify metal ions and determine their concentrations in dilute solutions.

A qualitative test in which a sample is heated in a flame and a characteristic flame colour may reveal the metal ion present.

How easily a substance catches fire and burns.

A substance that catches fire and burns readily.

The ability to bend without breaking.

The gases released after a fuel is burnt in a furnace or power station.

A pulling force between particles that helps keep them close together.

Attractive interactions that act between the particles of a substance.

Attractions that tend to hold the particles of a substance together.

An equation that represents a relationship between two or more quantities.

A mixture designed as a useful product, with components combined in carefully measured quantities to give the product its required properties.

The representative group of ions shown by the formula of an ionic substance, such as NaCl.