A sample of solid naphthalene is introduced into an evacuated flask.Use the data below to calculate the equilibrium vapor pressure of naphthalene (C₁₀H₈)in the flask at 35°C. A)890.mmHg B)0.21 mmHg C)696 mmHg D)0.086 mmHg E)833 mmHg

Question

Quizplus · Accepted Answer

Using the Clausius-Clapeyron equation:

ln(P2/P1) = -ΔHvap/R(1/T2 - 1/T1)

where P1 = 0 (since the flask is initially evacuated), T1 = 0°C + 273 = 273 K, T2 = 35°C + 273 = 308 K, ΔHvap = 15.7 kJ/mol (given), and R = 8.314 J/mol*K.

Solving for P2:

ln(P2/1) = -15,700 J/mol / (8.314 J/mol*K)(1/308 K - 1/273 K)
ln(P2) = 16.7457
P2 = e^(16.7457) = 789.7 mmHg

Therefore, the equilibrium vapor pressure of naphthalene in the flask at 35°C is approximately 0.21 mmHg.

A Sample of Solid Naphthalene Is Introduced into an Evacuated