3. enthalpy calculations

Question 1

what does Hess law say

Answer 1

the total enthalpy change of a reaction is always the same no matter which route is taken

Question 2

you can work out enthalpy changes from

Answer 2

1. enthalpies of formation

2. enthalpies of combustion

Question 3

how to calculate enthalpy changes using average bond enthalpy

Answer 3

enthalpy change of reaction = total energy absorbed (endo) - total energy release (exo)