Chapter 9- Enthalpy

Question 1

Define standard enthalpy change

Answer 1

The enthalpy change under standard conditions

Question 2

What are the standard conditions?

Answer 2

100kPa or 1 atm
298K or 25C
1 moldm^-3
Standard state- physical state of a substance under standard conditions

Question 3

Define Enthalpy change of reaction

Answer 3

Enthalpy change that accompanies a reaction in the molar quantities shown in a chemical equation under standard conditions, with all the reactants and products under standard state.

Question 4

Define enthalpy change of formation

Answer 4

Enthalpy change that takes place when one mole of a substance is formed from its constituent elements under standard conditions, with all the reactants and products in their standard state.

Question 5

Define enthalpy change of combustion

Answer 5

The enthalpy change that takes place when one mole of a compound reacts completely with oxygen under standard conditions, with all the reactants and products in their standard states.

Question 6

Define enthalpy change of neutralisation

Answer 6

The enthalpy change that accompanies the reaction of an acid by a base to form one mole of H2O, under standard conditions, with all reactants and products in their standard states.

Question 7

Define specific heat capacity

Answer 7

The energy required to raise the temperature of 1g if a substance by 1K.

Question 8

Define average bond enthalpy

Answer 8

Energy required to break one mole of a specified type of bond in a gaseous molecule.