IIT JEE , AIEEE Forum - Chemistry , Physical Chemistry

bupi

cal the heat of rxn at a constant pressure and that at a constant volume for the combustion of two moles of liq benzene at 25*C

smriti.mathur

Combustion equation of benzene for 2 moles-

2 C6H6 (l) + 15 O2 (g)

12 CO2 (g) +6 H2O ,

H= ?

H = (Enthalpy of products - Enthalpy of reactants)

=(12* del H(f) CO2(g) +6* del H(f) H2O) - (2* del H(f) C6H6(l) + 0)

=(12* -94.3 + 6* -68.4) - (2* +11.7)

= -1565.4 K. Cal

H= qp

E= qv

H=

E +

nRT

-1565.4=

E +(12 - 15)0.002 * 298

E= -1563.6