The reaction of cyan-amide, NH2CN(s), with dioxygen was carried out in a bomb calorimeter, and ΔU was found to be −742.7kJmol−1 at 298 K. Calculate enthalpy change for the reaction at 298 K. NH2CN(g)+32O2(g)→N2(g)+CO2(g)+H2O(l)
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Solution
NH2CN(g)+32O2(g)⟶N2(g)+CO2(g)+H2O(l)
From the above reaction,
Δng=nP−nR=(1+1)−(1+32)=−12
Given:-
ΔU=−742.7kJ/mol
T=298K
As we know that,
ΔH=ΔU+ΔngRT
⇒ΔH=−742.7+(−12×8.314×10−3×298)
⇒ΔH=−742.7−1.238=−743.938
Hence the enthalpy change for the given reaction is −743.938kJ/mol.