Question

Arsine, AsH3, is a highly toxic compound used in the electronics industry for the production of semiconductors. Its vapor pressure is 35 Torr at 111.95 C and 253 Torr at 83.6 C. Using these data, calculate (a) the standard enthalpy of vaporization;

Answer 1

Answer:

-79.8 × 10⁴ J/mol

Explanation:

Arsine, AsH₃, is a highly toxic compound used in the electronics industry for the production of semiconductors. Its vapor pressure is 35 Torr at 111.95 °C and 253 Torr at 83.6 °C.

Then,

P₁ = 35 torr

T₁ = 111.95 + 273.15 = 385.10 K

P₂ = 253 torr

T₂ = 83.6 + 273.15 = 356.8 K

We can calculate the standard enthalpy of vaporization (ΔH°vap) using the two-point Clausius-Clapeyron equation.

$ln(\frac{P_{2}}{P_{1}} )=\frac{-\Delta H\°_{vap}}{R} .(\frac{1}{T_{2}} -\frac{1}{T_{1}} )$

where,

R is the ideal gas constant

$ln(\frac{253torr}{35torr})=\frac{-\Delta H\°_{vap}}{8.314J/K.mol} .(\frac{1}{356.8K}-\frac{1}{385.10K})\\ \Delta H\°_{vap}=-79.8 \times 10^{4} J/mol$