Answer:
NH3+(3/2)CuO⟶21N2(g)+(3/2)H2O(l)+(3/2)Cu(s);ΔH=?
ΔH∘=ΣHProducts∘−ΣHReactants∘
=[21×HN2∘+(3/2)×HH2O(l)∘+ (3/2)HCu∘]−[(3/2)HCuO∘+HNH3∘]
=[0+(3/2)×(−285)+(3/2)×0]−[(3/2)×(−155)+(−46)]
=−149kJ
[∵H∘forpureelement=0andHcompound∘=Hform
