4 Bond enthalpies Flashcards
1
Q
What is meant by ‘mean bond enthalpy’?
A
The average enthalpy change when 1 mole of bonds in gaseous molecules are broken
2
Q
How do we calculate the enthalpy change for reactions in the gaseous phase?
A
ΔH = ∑ bond energies broken - ∑ bond energies made
3
Q
Why do values from mean bond enthalpy calculations differ from those determined by Hess’s law?
A
Mean bond enthalpy calculations use mean values while Hess’s law uses enthalpy data from individual compounds
4
Q
Bond breaking __________ energy
A
requires
5
Q
Bond making ___________ energy
A
releases
