As, (Cp−Cv)=R⇒Cp=Cv+R
⇒Cp=32R+R=52R
Heat given at constant pressure
ΔH=nCpΔT=1×52R(373−298)
⇒ΔH=1×52×2×75=375 cal
Work done in the process =−PΔV
=−P(V2−V1)
=−P(nRT2P−nRT1P)
(As, PV = nRT because the process is carried out reversibly)
=−nR(T2−T1)
=−1×2(373−298)
=−150 cal
From first law of Thermodynamics,
ΔE=q+W
=375−150=225 cal