What are standard conditions?
- Pressure of 100 kPa
- temperature of 298K
Describe the standard enthalpy change of combustion.
The enthalpy change when one mole of a substance reacts completely with oxygen under standard conditions in their standard states.
Describe the standard enthalpy change of formation.
The enthalpy change that takes place when one mole of a compound is formed from its constituent elements in their standard states, under standard conditions.
What is the standard enthalpy change of formation for all elements?
0 KJ/mol
Describe the standard enthalpy change of neutralisation.
The enthalpy change that takes place when an acid reacts with a base to form one mole of water under standard conditions, in their standard states.
Why are the standard values from the data book different to calculated values?
- Incomplete combustion
- heat loss to surroundings
- evaporation
- non-standard conditions
