Short Answer TypeGiven:
What is the standard enthalpy of formation of NH3 gas?
The enthalpy of formation of ammonia is the enthalpy change for the formation of 1 mole of ammonia from its elements.
Given that enthalpy of formation for 2 moles of NH3 = –92.4 kJ
Therefore, standard enthalpy of formation for
Hence standard enthalpy of formation for NH3
Calculate the enthalpy change of reaction:
at 298K, given that the enthalpies of formation at 298 K for 
Enthalpies of formation of CO(g), CO2(g), N2O(g) and N2O4 (g) are -110, -393, 81 and 9.7 kJ mol-1. Find the value of 
for the reaction:
N2O4 (g) + 3CO(g) 
N2O(g) + 3CO2(g)
Long Answer TypeThe combustion of one mole of benzene takes place at 298K and 1 atm. After combustion, CO2(g) and H2O(l) are produced and 3267.0 kJ of heat is liberated. Calculate the standard enthalpy of formation of ∆fH° benzene, given that standard enthalpy of formation of CO2(g) and H2O(l) are –393.5 kJ mol–1 and –285.83 kJ mol–1respectively.
Short Answer TypeLong Answer TypeExplain why enthalpy of neutralization of a strong acid and strong base remains the same and the value changes if one of them is weak.
Explain the following:
(i) Enthalpy of fusion
(ii) Enthalpy of vaporization
(iii) Enthalpy of sublimation.
Short Answer Type
Switch
if the heats of formation of 
respectively.
