A-Level chemistry enthalpy changes

Standard enthalpy change of reaction

The enthalpy change that accompanies a reaction in the molar quantities as shown in the chemical equation equation under standard conditions and states

Standard enthalpy change of combustion

The enthalpy change that occurs when 1 mol of a substance combusts completely in oxygen under standard conditions and states

Standard enthalpy change of formation

The enthalpy change that occurs when 1 mol of a compound is formed from its constituent elements under standard conditions and states

Standard enthalpy change of neutralisation

The enthalpy change that accompanies the reaction of a base reacting with an acid to form 1 mol of water under standard conditions and states

Average bond enthalpy

The energy required to break 1 mol of covalent bonds in the gas phase averaged over chemical environments

Standard lattice enthalpy

The enthalpy change that occurs when forming 1 mol of an ionic lattice from gaseous ions under standard conditions and states

First ionisation energy

The energy required to remove one electron from each atom in 1 mol of atoms to form 1 mol of gaseous +1 ions under standard conditions and states

Standard enthalpy change of hydration

The enthalpy change that occurs when 1 mol of gaseous ions dissolve in liquid water to form 1 mol of aqueous ions under standard conditions and states

Standard enthalpy change of solution

The enthalpy change that occurs when 1 mol of a solute dissolves completely in a solution under standards and states

What does first electron affinity mean

When one electron is adde to each atom in 1 mol gaseous ions to form gaseous 1- ions

What does standard enthalpy change of atomisation mean

The enthalpy change when forming of mol of gaseous atoms from elements

How does increasing the mass of a solid affect the temperature change and enthalpy change of solution

• temperature change increases as more energy is produced in the same volume of water

• Enthalpy change of solution stays the same because the ratio of energy produced to mass is still the same

How does enthalpy changes change with different halide ions

Enthalpy changes become less negative down group 7 because the ions increase in atomic radius which decreases nuclear attraction