How much energy must be removed from a 125 g sample of benzene (molar mass = 78.11 g mol^-1) at 425.0 K to liquify the sample and lower the temperature to 335.0 K? The following physical data may be useful: Δ_vapH = 33.9 kJ mol^-¹
Δ_fusH = 9.8 kJ mol^-1
C_liq = 1.73 J g^-1 °C^-1
C_gas= 1.06 J g^-1 °C^-1
C_sol = 1.51 J g^-1 °C^-1
T_melting= 279.0 K
T_boiling = 353.0 K

Question

Quizplus · Accepted Answer

To solve this, calculate the energy removed in three steps: 1) Condense benzene from gas to liquid at 353 K using Δ_vapH, 2) Cool the liquid benzene from 353 K to 335 K using C_liq, and 3) Sum the energies. The total energy removed is approximately 67.7 kJ.

How Much Energy Must Be Removed from a 125 G