Question

Methyl salicylate, C8H8O3, the odorous constituent of oil of wintergreen, has a vapour pressure of 1.00 torr at 54.3oC and 10.0 torr at 95.3oC.

a. What is its vapour pressure at 25oC?
b. What is the minimum number of liters of air that must pass over a sample of the compound at 25oC to vaporize 1.0 mg of it?

Answer 1

To determine the vapor pressure of methyl salicylate at 25°C, use the Clausius-Clapeyron equation. To find the minimum number of liters of air needed to vaporize 1.0 mg of methyl salicylate at 25°C, use the equation mass = volume * density.

Step-by-step explanation:

To determine the vapor pressure of methyl salicylate at 25°C, we can use the Clausius-Clapeyron equation, which states that ln(P2/P1) = (ΔHvap/R)((1/T1) - (1/T2)), where P1 and P2 are the vapor pressures at temperatures T1 and T2 respectively, ΔHvap is the enthalpy of vaporization, and R is the ideal gas constant. Rearranging the equation, we have P2 = P1 * (T2/T1)^((ΔHvap/R)). Plugging in the given values, we can solve for P2. To find the minimum number of liters of air needed to vaporize 1.0 mg of methyl salicylate at 25°C, we will need to know the density of the compound. Once we have the density, we can use the equation mass = volume * density to solve for the volume of air needed.

Answer 2

Use the Arrhenius equation. Use p1 and p2 and T1 and T2 and solve for Ea (actgivation energy) in Joules, then plug that back into the Arrhenius equation and either p1 or p2 to calculate p at 25C.