Posted by Taylor on .
Calculate Delta H for 4NH3 + 5O2 > 4NO + 6H2O
using:
N2 +O2 > 2NO DH= 180.5 kJ
N2 + 3H2 > 2NH3 DH= 91.8 kJ
2H2 + O2 > 2H2O DH= 483.6 kJ

Chemistry 
DrBob222,
Hess' Law.
Multiply equation 2 by 2 and reverse it.
Multiply equation 3 by 3 and leave as is.
Multiply equation 1 by 2 and leave as is.
Add the resulting equations.
Add the resulting delta Hs also, (after multipling AND changing the sign of those reversed.