OCR GCSE Chemistry B key terms

A visual representation used to display data or the relationship between variables.

A single, one-atom-thick sheet of carbon atoms joined in a hexagonal pattern.

The warming of the Earth’s surface and lower atmosphere because atmospheric gases absorb and emit some of the infrared radiation emitted by the Earth.

A gas in the atmosphere that absorbs infrared radiation emitted by the Earth and re-emits it in all directions, helping to warm the surface and lower atmosphere.

A vertical column of elements in the Periodic Table. Elements in Groups 1–7 share the same number of outer-shell electrons within each group. Group 0 elements have full outer shells, but helium has two outer-shell electrons while the others have eight.

The elements in the far-right column of the Periodic Table; they are very unreactive gases at room temperature and pressure.

The metals in the first column of the Periodic Table, whose atoms each have one electron in their outer shell.

An industrial method of making ammonia by reacting nitrogen with hydrogen.

A chemical equation showing one electron-transfer change, with electrons written explicitly as reactants or products.

An equation showing the electrons lost or gained by one species during a redox reaction.

A compound formed when a halogen combines with another element, such as sodium chloride.

A negatively charged ion formed when a halogen atom gains an electron, such as chloride, bromide or iodide.

A Group 7 element, such as chlorine, bromine or iodine.

The ability of a material to resist being scratched, dented or deformed.

Something with the potential to cause harm, such as a corrosive chemical, a flame, hot glass or a trailing electrical lead.

A family of organic compounds with similar structures and chemical properties; successive members differ by a repeating unit.

A compound containing carbon and hydrogen atoms only.

A positively charged ion, written as $\mathrm{H^+}$, whose concentration determines the pH of a solution.

The amount of hydrogen ions, $H^+$, present per unit volume of a solution.

A fuel cell in which hydrogen reacts with oxygen, transferring chemical energy mainly as electrical energy and producing water.

A negatively charged ion represented by OH⁻.

A tentative scientific explanation for an observed phenomenon that can be tested using evidence.

Unwanted material mixed with the substance being tested.

The burning of waste; the energy released may be used to generate electricity.

Combustion in which there is insufficient oxygen for all the fuel to be fully oxidised.

An increase in the mass of crop harvested from an area of land.

The variable placed on the horizontal axis; it is usually the variable that is changed or used to organise the data.