Question

The US Food and Drug Administration lists dichloromethane (CH2Cl2) and carbon tetrachloride (CCl4) among the many cancer causing volatile chlorinated organic compounds. An autoshop you are employed at keeps a jar (closed) of this solution to use as a solvent for cleaning parts. If the jar contains 1.60mol of dichloromethane and 1.10mol of CCl4, what would be the total pressure in the jar if the shop is kept at a consistent 23.5C

Answer 1

Answer:

The pressure of the solution is 256.7 torr

Explanation:

It is possible to answer this question using Raoult's law that states the pressure of a solution -or mixture- is equal to the vapour pressure of the pure solvent multiplied by its mole fraction in the solution. For the problem:

$P_{solution} = P^0_{CH_2Cl_2}*X_{CH_2Cl_2} + P^0_{CCl_4}*X_{CCl4}$

Where P° is vapour pressures of pure solvents (352torr for dichloromethane and 118torr for carbon tetrachloride)

And X is mole fraction:

X dichloromethane: 1.60 mol / (1.60mol + 1.10mol) = 0.5926

X tetrachloride: 1.10 mol / (1.60mol + 1.10mol) = 0.4074

Replacing:

$P_{solution} = 352torr*0.5926 + 118torr*0.4074$

$P_{solution} = 256.7torr$

The pressure of the solution is 256.7 torr