Standard enthalpies

Question 1

Standard enthalpy change of formation

Answer 1

The energy released or consumed when one mole of a substance is created under standard conditions from its pure elements

Question 2

Standard enthalpy change of combustion

Answer 2

When one mole of a compound is completely burnt in the presence of oxygen with all reactants and products in their standard state under standard conditions

Question 3

Standard enthalpy change of reaction

Answer 3

The amount of heat evolved or absorbed in a reaction carried out at constant pressure

Question 4

Standard enthalpy change of neutralisation

Answer 4

When solutions of an acid and an alkali react together under standard conditions to produce 1 mole of water

Question 5

Specific heat capacity

Answer 5

Amount of heat needed to raise the temperature of 1g of a substance by 1K

Question 6

Hess’s law

Answer 6

Hess’s law states that the enthalpy change for a chemical reaction is the same, whatever route is taken from reactants to products

Question 7

Enthalpy change

Answer 7

Heat energy change at constant pressure