Question

solid benzoic acid at constant volume is -300.3 Kj 27 degree centigrade the heat of combustion at constant pressure is

Answer 1

Hey dear,

◆ Answer-
-301.547 kJ

◆ Explaination-
# Given-
∆H(cv) = -300.3 kJ = -300.3×10^3
T = 27 °C = 300 K

# Solution-
Combustion of benzoic acid occurs as -
C6H5COOH(s) + 15/2 O2(g) ---> 7CO2(g) + 3H2O(l)

Change in no of moles is-
∆n = 7-15/2 = -0.5

Heat of combustion at constant pressure is given by-
∆H(cp) = ∆H(cv) + ∆nRT
∆H(cp) = -300.3×10^3 + (-0.5)×8.314×300
∆H(cp) = −301547.1 J
∆H(cp) = −301.547 kJ

Heat of combustion at constant pressure is -301.547 kJ.

Hope this helps...