OCR GCSE Chemistry B key terms

A change in which one or more new substances with different chemical identities are formed.

A symbolic representation that identifies the elements in a substance and shows their relative numbers or ratio.

Features that describe how a substance behaves in chemical reactions, such as the kinds of compounds it forms.

A property describing how a substance reacts and forms new substances.

A process in which atoms are rearranged as bonds are broken or formed, usually involving changes in the arrangement of outer-shell electrons.

A measure of how readily a substance undergoes chemical reactions.

A one- or two-letter abbreviation for an element, representing one atom of that element when used on its own.

The controlled addition of chlorine to water to kill harmful microorganisms.

The pattern of separated spots produced when a mixture is carried through a stationary phase by a mobile phase.

Separating dissolved substances according to how they move with a solvent over a stationary material.

A long-term change in average climate conditions or in the pattern of weather, including temperature, rainfall and extreme events.

Information about climate variables, such as temperature or atmospheric composition, collected over time or across locations.

A simplified representation of a system used to explain observations or make predictions.

A system in which matter cannot enter or leave, although energy may be transferred between the system and its surroundings.

The number $a$ in $a \times 10^n$. In standard form, it is at least 1 but less than 10.

The simplest whole-number proportions of the reactants and products in a balanced equation.

The number of collisions occurring in a given time, such as each second.

A model explaining reaction rate through how often reacting particles collide and whether those collisions have enough energy to cause a reaction.

A reaction in which a substance reacts with oxygen and releases energy. Complete combustion of the organic compounds considered here produces carbon dioxide and water.

A material formed by combining two or more materials so that useful properties are produced.

A material made by combining different materials so that useful properties from them are brought together.

A substance made from atoms of two or more different elements chemically bonded together in fixed proportions.

An ion made from two or more atoms joined together that acts as one charged unit, such as $\mathrm{NO_3^-}$.

A unit formed from more than one unit, usually by multiplication or division, such as $\text{g/dm}^3$ or $\text{m/s}$.

The ability of a material to withstand a crushing force without failing.

A model implemented using computer code so that many calculations or simulations can be carried out efficiently.

An acid solution containing a relatively large amount of acid per unit volume.