Enthalpy Calculations Flashcards
1
Q
What does Hess’s Law say?
A
The total enthalpy change of a reaction is always the same, independent of the route taken.
2
Q
What is AfH for elements?
A
0
3
Q
In which direction do the enthalpy of formation arrows point?
A
Upwards
4
Q
By Hess’s Law, what is the calculation for enthalpy changes of formation?
A
A=C-B
5
Q
In which direction do the enthalpy of combustion arrows point?
A
They point downwards.
6
Q
By Hess’s Law, what is the calculation for enthalpy changes of combustion?
A
A=B-C
7
Q
How do you calculate enthalpy changes using average bond enthalpies?
A
Enthalpy change of reaction= total energy absorbed-total energy released.
