OCR GCSE Chemistry B key terms

A factor under which a reaction takes place, such as reactant concentration or temperature.

A way of making a specified chemical, which may involve one reaction or a series of reactions.

A graph showing how the energy of a reacting system changes as reactants are converted into products.

The amount of a reactant used or product formed per unit time.

A measure of how readily a substance undergoes a chemical reaction.

A list of metals arranged from the most reactive at the top to the least reactive at the bottom.

Rewriting an equation to make a different variable its subject without changing the relationship it expresses.

A judgement that answers the question being investigated and is supported by relevant evidence and scientific reasoning.

Processing waste material so that it can be used to make new material or products.

A reaction in which oxidation and reduction occur together through the transfer of electrons.

A substance that causes another species to be reduced by donating electrons; the reducing agent is itself oxidised.

A reaction in which a species gains electrons.

A spectrum from a known substance used for comparison with an unknown sample.

A trusted value for a known substance, used for comparison with an experimental result.

Planting trees to restore or establish forest, allowing growing trees to take in carbon dioxide by photosynthesis.

The mass of an atom compared with a standard reference mass; its value, Aᵣ, has no unit.

The average mass of an atom of an element compared with one-twelfth of the mass of a carbon-12 atom; it has no unit.

A comparison between the charge of one particle and the charges of other particles, using simple numbers rather than coulombs.

The sum of the relative atomic masses of all the atoms shown in a chemical formula.

The sum of the relative atomic masses of all the atoms shown in a chemical formula; it has no unit.

A comparison between particle masses in which the approximate mass of a proton is assigned the value 1.

A value used to compare reaction speeds when an exact rate is not calculated; for a fixed endpoint it can be represented by $1/t$.

A comparison of the sizes of two objects, normally made after expressing both measurements in the same unit.

The closeness of results obtained when the same person repeats a measurement using the same method and equipment.

The section of a polymer chain that repeats many times along its length.

The smallest section of a polymer chain that repeats along the chain.

A model that represents a system using objects, images, symbols or an analogy, such as a ball-and-stick molecule.