Bond Energies?

Question

When a chemist burns hydrogen according to the reaction below she finds that heat is released. (It is exothermic.)
2H2(g) + O2(g) 2H2O(g)

The enthalpy change for the reaction is H = -484 kJ. What is the enthalpy change per gram of hydrogen (in kJ/g)?

Answer 1

4zx(Y)- H2O CHI3

Answer 2

The enthalpy change refers to 1 mole of the reaction as written. So to find the energy per g hydrogen, simply divide this by the number of g hydrogen that go into the reaction.

Answer 3

-121kj/gram

H = 1 g per mole therefore 4 moles of H in the reaction.
-484/4