In the given reaction, C2H4(g)+3O2(g)→2CO2(g)+2H2O(l) ΔH=−1410.0kJ For ideal gas, ΔH=ΔU+RT(Δng) where, R=8.314J/ molK T=298K Δng= number of gaseous products - number of gaseous reactants =2−4=−2 ∴−1410=ΔU+[8.314×298(−2)] ΔU=−1405.045kJ ∼eq−1405.05kJ Now, ΔH−ΔU=−1410−(−1405.05)=−4.95kJ