OCR GCSE Chemistry B key terms

The force exerted per unit area; for a gas, it can be increased by compressing the gas into a smaller volume.

A numbered, repeatable sequence of practical instructions stating what must be done, measured and recorded.

A diagram using boxes and arrows to show materials entering, moving through and leaving the stages of a process.

A substance formed by a chemical reaction.

The new substances formed in a chemical reaction.

A way of representing a three-dimensional object on a two-dimensional surface.

The amount of one component compared with the amounts of the other components in a mixture.

A naturally occurring polymer made from amino acid monomers.

A positively charged subatomic particle found in the nucleus, with a relative mass of 1.

An indirect measurement used to reconstruct past conditions when direct measurements are unavailable, such as evidence from ice cores or tree rings.

A substance consisting of just one element or one compound, rather than a mixture.

A method of removing unwanted substances from a material to make the desired substance purer.

Analysis that identifies which substances or components are present, rather than measuring how much of each is present.

Descriptive, non-numerical data about qualities such as colour, state or appearance.

A description or observation rather than a numerical measurement, such as a colour change or the formation of a precipitate.

A test substance that produces an observable result which helps to identify an unknown substance or product.

A test that identifies a substance from an observation, such as a flame colour or a precipitate, rather than measuring how much is present.

The investigation of a sample using measurements and calculations to determine how much of a substance is present.

Data expressed using numbers, such as a mass, temperature, count or time.

A numerical measurement accompanied by an appropriate unit.

Energy transferred as electromagnetic waves; it can travel through a vacuum and may be transmitted, reflected or absorbed when it meets matter.

Unpredictable variation that makes repeated measurements differ and produces scatter in the data.

A measure of spread calculated by subtracting the lowest value from the highest value.

A vertical line on a graph extending from the lowest to the highest repeat measurement at one value of the independent variable.

How quickly reactants are converted into products.

A comparison obtained by dividing one quantity by another.

The scientific purpose and reasoning behind an investigation, including what is being tested and why the chosen approach can provide relevant evidence.

The basic materials from which a product is made, obtained from sources such as the Earth's crust, atmosphere, oceans or living organisms.