At 28 degrees Celsius, the vapor pressure of n-propyl mercaptan C3H7SH is 175 to

Question

At 28 degrees Celsius, the vapor pressure of n-propyl mercaptan C3H7SH is 175 torr, while that of acetonitrile CH3CN is 102 torr. What is the vapor pressure at 28 degrees Celsius of a solution made by mixing 120.0 g of C3H7SH and 80.0 g CH3CN if Raoult’s Law is obeyed? At 28 degrees Celsius, the vapor pressure of n-propyl mercaptan C3H7SH is 175 torr, while that of acetonitrile CH3CN is 102 torr. What is the vapor pressure at 28 degrees Celsius of a solution made by mixing 120.0 g of C3H7SH and 80.0 g CH3CN if Raoult’s Law is obeyed?

Explanation / Answer

Answer:-

Step 1)

C3H7SH has a molecular weight of 76.16g/mol

CH3CN has a molecular weight of 41.05g/mol

Step 2) So there are we find how many number of mole are present in both compound

For n-propyl mercaptan

120g × (1 mol / 76.16 g) = 1.576 mol

For acetonitrile

80g × (1mol / 41.05 g ) = 1.949 mol

Step 3) we calculate the mole fraction of both compound

We need total number of mole so,

1.576 mol + 1.949 mol = 3.525 moles in total

For n-propyl mercaptan

1.576 mol / 3.525 mol = 0.4471

For acetonitrile

1.949 mol / 3.525 mol = 0.5530

Step 4) So the vapor pressure of the mixture is just vapor pressure of

vapor pressure = Pure material × mole fraction,

all added together,

Vapor pressure = (175 × 0.4471) + (102 × 0.5530)

Vapor pressure = 134.65 torr

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.