The molar enthalpy of vaporization of benzene at its boiling point (353 K) is 7.4 kcal/mol. The molar internal energy change of vaporization is

Question

TestHub · Accepted Answer

The relationship between internal energy change (Δ U) and enthalpy change (Δ H) is given by:

Δ U = Δ H - Δ n_g RT

Given Δ n_g = 1, we can calculate the Δ n_g RT term:

Δ n_g RT = 1 × 2 × 10^⁻³ × 353 = 0.706 kcal

Now, substitute this value back into the equation for Δ U:

Δ U = 7.4 - 0.706 = 6.694 kcal/mol

This corresponds to option (c).

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