OCR GCSE Chemistry B key terms

The insoluble solid left on filter paper after filtration.

The smallest change in a quantity that a measuring instrument can distinguish.

Using a product again without breaking it down into raw material.

A reaction in which the products can react to form the original reactants.

The distance travelled by a substance divided by the distance travelled by the solvent front, both measured from the baseline.

The chance that a hazard will cause harm, considered together with how serious that harm could be.

The process of identifying hazards, judging their risks and selecting suitable control measures.

A structured comparison of the advantages and possible harms of an action, including who receives the benefits and who bears the risks.

A judgement that compares the advantages of an application with its possible harms.

A factor that changes the probability of an outcome without producing that outcome in every case.

A step taken to make harm less likely or to limit its effects while, where possible, retaining the benefits of an activity.

The usual conditions under which the molar gas volume is taken to be 24 dm³ mol⁻¹ for GCSE calculations.

Changing a number to a stated precision while keeping its value as close as possible to the original.

The corrosion of iron or steel in the presence of both oxygen and water, producing hydrated iron(III) oxide.

Protection in which a more reactive metal is oxidised instead of the metal being protected.

A substance formed when the hydrogen ions of an acid are replaced by metal ions or another positive ion.

A small portion taken from a larger amount of material for testing.

The number of independent observations, objects, specimens or experimental units included in an investigation.

A solution that cannot dissolve any more of a particular solute at that temperature.

A measure of how large or small something is compared with another object or a stated length.

The number by which a quantity is multiplied when it changes, such as 2 for a doubling.

The sharing of scientific questions, methods, evidence, conclusions and significance in a form suited to its intended recipients.

A development in scientific knowledge, understanding or methods.

A scientific account that connects evidence and accepted ideas to explain how or why something happened.

A systematic process of posing questions, gathering and analysing evidence, considering alternative explanations and communicating conclusions.

A simplified description or representation of a system that identifies important features and rules for how they interact.

A measurable property written as a numerical value with an appropriate unit, such as a time of 30 s.