OCR GCSE Chemistry B key terms

A way of writing a number as $a \times 10^n$, where $1 \leq a < 10$ and $n$ is an integer.

The physical form of a substance, such as solid, liquid or gas.

A symbol in brackets showing a substance's physical state: (s), (l), (g) or (aq).

The phase that stays in place during chromatography; in paper chromatography, it is the paper.

A family of alloys based on iron, usually containing carbon and sometimes other elements.

Resistance to bending or changing shape.

The ratio between the amounts in moles of substances, given by the coefficients in a balanced chemical equation.

The numerical relationship between the amounts of reactants and products in a balanced chemical equation.

An acid that ionises completely in water.

A formula showing how the atoms in a molecule are connected. A fully displayed formula shows every atom and every covalent bond.

A particle smaller than an atom, such as a proton, neutron or electron.

The variable that is isolated on one side of an equation, so that the equation gives its value.

The change of state from solid directly to gas, without passing through the liquid state.

A small number written at the lower right of a symbol or bracketed group to show how many of that atom or ion are present.

The substance on which an enzyme acts.

A collision between reactant particles that leads to a reaction.

A gas with the formula SO₂, formed when sulfur impurities in a fuel burn in oxygen.

A number written at the upper right of an ion's formula to show the size and sign of its electrical charge.

The total area of a solid that is exposed to the other reactant or reactants.

A solid’s surface area divided by its volume; it compares how much surface is available with how much solid there is.

A comparison between the total area of an object's outside surface and the space occupied by the object.

Everything outside the reacting chemicals; in this investigation it includes the solution, cup, thermometer and nearby air.

The ability of a process to meet current demand without causing long-term environmental harm.

Using natural resources at a rate that allows them to be replaced, so their use can continue into the future.

Meeting present needs while conserving resources and limiting environmental damage so that future needs can also be met.

An equation using chemical formulae to show the reactants and products of a chemical reaction.

An error that shifts measurements consistently away from the true value, usually in the same direction.