AQA GCSE Chemistry Key Terms

Simple diagrams showing alternating charges, but failing to show the 3D structure or multi-directional nature of electrostatic forces.

The percentage or proportion of each isotope that occurs naturally for a particular element.

How close a measurement is to the true value of the quantity being measured.

A substance that produces hydrogen ions ($H^+$) when dissolved in aqueous solutions.

An acidic substance, such as concentrated sulfuric acid, used to speed up esterification without being used up itself.

A non-metal oxide that reacts with a base or alkali to form a salt and water.

The process of adding acid to a sample to remove interfering impurities before adding a test reagent.

Toxic, acidic runoff from mining sites that can leach heavy metals into nearby groundwater.

Rainwater with an unusually low pH, caused by dissolved sulfur dioxide and oxides of nitrogen forming dilute acids.

The minimum energy required to start the bond-breaking process in the reactants.

The minimum amount of energy that particles must have to react upon collision.

The specific chemical component in a medicine that actively treats the targeted medical condition.

The specific region on an enzyme where the substrate binds and the chemical reaction takes place.

The recorded amount of product physically obtained from a chemical reaction through experimentation.

A reaction where many small molecules (monomers) join together to form very large molecules (polymers) and no other product is formed.

A reaction where the double bond of an alkene opens up and atoms are added to the carbon atoms.

A process where reactant molecules stick to the surface of a solid catalyst, weakening their bonds and bringing them closer together.

A stage where aerobic bacteria break down organic matter and harmful microbes in effluent in the presence of oxygen.

The measure of reflectivity of a surface, where lighter surfaces (like ice) reflect more solar radiation than dark surfaces.

Simple, photosynthetic organisms that were the first to significantly alter the Earth's atmosphere by producing oxygen 2.7 billion years ago.

A soluble base that produces hydroxide ions ($OH^-$) in aqueous solutions.

The highly reactive metals found in Group 1 of the periodic table, including lithium, sodium, and potassium.

Common examples of non-rechargeable cells that must be discarded once a reactant is used up.

A solution with a pH greater than 7, formed when Group 1 hydroxides dissolve in water.

Soluble bases that produce hydroxide ions in aqueous solution.

A homologous series of saturated hydrocarbons with the general formula $C_nH_{2n+2}$.

A homologous series of unsaturated hydrocarbons with the functional group $C=C$ and the general formula $C_nH_{2n}$.

Different structural forms of the same element in the same physical state.

A physical mixture of two or more elements, at least one of which is a metal, containing atoms of different sizes.

Positively charged particles consisting of two protons and two neutrons (a helium nucleus) used in Rutherford's scattering experiment.