Answer is: .408,5 J.m(C₆H₆-benzene) = 39 g.
n(C₆H₆) = m(C₆H₆) / M(C₆H₆) = 39g ÷ 78g/mol = 0,5 mol.ΔT = 10,0°C, difference at temperature.c(benzene) = 81,7 J/mol·°C, specific heat of benzene.Q = n(benzene) · ΔT · c(benzene), heat of reaction.Q = 0,5 mol · 10,0°C · 81,7 J/mol·°C.Q = 408,5 J.