Question

The vapor pressure of liquid iodomethane, CH3I, is 100. mm Hg at 266 K. A 0.271 g sample of liquid CH3I is placed in a closed, evacuated 480. mL container at a temperature of 266 K. Assuming that the temperature remains constant, will all of the liquid evaporate? What will the pressure in the container be when equilibrium is reached? ------ mm Hg

Answer 1

Answer.

We have been given that

gas constant (R) = 0.08205 L-atm/mol-K

volume of container (V) = 480 mL = 0.48 L

temperature (T) = 266 K

mass of sample (m) = 0.271 g

molar mass of sample (M) = 142 g/mol

using pV=nRT (ideal gas equation), we have

p*0.48 = (0.271/142)*0.08205*266

p = 0.08678 atm = 66 mm of Hg.

Therefore, pressure due to liquid is 66 mm of Hg.

No, all the liquid will not evaporate as total pressure would have been 100 mm Hg.

Pressure at equilibrium = 66 mm of Hg.