OCR GCSE Chemistry A Key Terms

A diamine monomer used to make polyamides like Nylon; it contains two amino (-NH₂) groups.

A type of chemical drawing that shows all the atoms and bonds in a molecule in a flat, 2D layout, often using 90° lines that do not represent true bond angles.

A physical model or drawn diagram that illustrates the true spatial arrangement of atoms and bonds in three dimensions.

A diagram showing how tightly ions pack together in a lattice, though it makes the internal 3D arrangement hard to see.

The specific way that atoms are organised and positioned in three-dimensional space within a molecule.

The estimated point in time when the Earth formed and volcanic activity began creating the early atmosphere.

How close a measured value is to the true or actual value.

A substance that releases hydrogen ions ($H^+$) when dissolved in water (aqueous solution).

The process where acidic solutions dissolve and carry away metal compounds from rocks or soil into water bodies, often caused by mining.

A non-metal oxide that reacts with a base to produce a salt and water, and often forms acidic solutions when dissolved.

A strong oxidising agent (formula KMnO₄) mixed with acid, used to oxidise alcohols into carboxylic acids.

The property of a solution having a pH less than 7 and a high concentration of hydrogen ions.

A dangerous, difficult-to-collect vapor produced if sulfur trioxide is added directly to water during the Contact process.

Precipitation with a pH typically lower than 5.5, caused by atmospheric pollutants like sulfur dioxide and nitrogen oxides dissolving in cloud water.

The minimum amount of energy that reactant particles must possess for a collision to be successful and result in a reaction.

The minimum amount of energy that colliding particles must possess for a chemical reaction to occur.

The minimum energy that colliding particles must possess for a chemical reaction to occur.

The specific chemical component in a pharmaceutical formulation that treats a medical condition.

The specific region on an enzyme's surface where the substrate binds and the chemical reaction occurs.

The specific locations on the surface of a catalyst where chemical reactions take place.

The measured mass or amount of product actually obtained and collected at the end of a chemical reaction.

A chemical reaction where many small unsaturated molecules join together to form one long polymer chain, with no other products formed.

A chemical reaction where two or more molecules combine to form a single larger product, with no other products formed.

The process where reactant molecules stick to the surface of a solid catalyst, weakening their bonds so they react more easily.

The process of using oxygen to break down glucose to release energy, which only became possible once atmospheric oxygen levels were high enough.

The natural attraction or force of interaction between a substance and the stationary phase.

Coarse-to-medium-grained particulate material, such as crushed stone or glass, used extensively in construction and road building.

An opening at the base of a Bunsen burner that can be adjusted using the collar to control the oxygen supply.

A homologous series of organic compounds containing the $-OH$ functional group.

A diverse group of aquatic, photosynthetic organisms that evolved roughly 2.7 billion years ago and began producing the Earth's first oxygen.