Grade 12 Chemistry notes

Bwoah

Molar mass

The mass in grams of one mole of a substance

Solution

A homogeneous mixture of solute and solvent

Solute

The substance that is dissolved

Solvent

The substance that dissolves another substance

Concentration

Amount of solute per unit volume of solution

Standard solution

A solution of known concentration

Intramolecular bond

A bond between atoms within a molecule

Electronegativity

The tendency of an atom to attract a bonding pair of electrons

Covalent bond

Sharing of at least one pair of electrons between two non-metal atoms

Non-polar covalent bond

Equal sharing of electrons

Polar covalent bond

Unequal sharing of electrons that creates a dipole

Ionic bond

Transfer of electrons and resulting electrostatic attraction

Metallic bond

Attraction between positive metal kernels and delocalised electrons

Intermolecular force

Weak attraction between molecules

Heat of reaction (ΔH)

Net change in chemical potential energy of a system

Exothermic reaction

Reaction that releases thermal energy

Endothermic reaction

Reaction that absorbs thermal energy

Activation energy

Minimum energy needed to start a reaction or form the activated complex

Activated complex

High-energy unstable transition state between reactants and products

Reaction rate

Change in concentration per unit time

Catalyst

Substance that speeds up a reaction and remains unchanged

Closed system

A system where mass is conserved but energy can enter or leave

Open system

A system where matter and energy can be exchanged

Le Chatelier’s Principle

When a system in equilibrium is stressed it shifts to oppose the stress

Yield

The extent of reaction compared to maximum possible product

Lowry–Brønsted acid

Proton (H⁺) donor

Lowry–Brønsted base

Proton (H⁺) acceptor

Ionisation

Reaction of a molecular substance with water to form ions

Dissociation

Splitting of an ionic compound into its ions

Strong acid

An acid that ionises completely in water

Strong base

A base that dissociates completely in water

Weak acid

An acid that ionises partially in water

Weak base

A base that dissociates or ionises partially in water

Amphoteric

A substance that can act as an acid or a base

Salt

A substance where hydrogen of an acid is replaced by a cation

Hydrolysis of a salt

Reaction of an ion from a salt with water

Neutralisation/Equivalence point

Point where an acid and base have reacted completely

Redox reaction

A reaction involving the transfer of electrons

Oxidation

Loss of electrons

Reduction

Gain of electrons

Oxidising agent

Substance that accepts electrons

Reducing agent

Substance that donates electrons

Anode

The electrode where oxidation occurs

Cathode

The electrode where reduction occurs

Electrolyte

Substance that conducts electricity when molten or in solution

Functional group

Atom or group of atoms responsible for chemical behaviour

Hydrocarbon

Compound containing only carbon and hydrogen

Homologous series

Series of compounds with same functional group and general formula differing by CH₂

Saturated compound

Compound with only single bonds between carbon atoms

Unsaturated compound

Compound with at least one double or triple carbon–carbon bond

Structural isomer

Compounds with the same molecular formula but different structures