What is the vapor pressure at 20 °c of an ideal solution prepared by the addition of 7.38 g of the nonvolatile solute urea, co (nh2) 2, to 56.9 g of methanol, ch3oh? the vapor pressure of pure methanol at 20 °c is 89.0 mm hg.

a. 5.75 mm hg

b?

Question

Chemistry

Cole Henson

25 August, 17:12

What is the vapor pressure at 20 °c of an ideal solution prepared by the addition of 7.38 g of the nonvolatile solute urea, co (nh2) 2, to 56.9 g of methanol, ch3oh? the vapor pressure of pure methanol at 20 °c is 89.0 mm hg.

a. 5.75 mm hg

b?

+4

Answers (1)

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Heidi · Answer 1

83.24 mmHg.

Explanation:

The vapor pressure of the solution (Psolution) = (Xmethanol) (P°methanol).

where, Psolution is the vapor pressure of the solution,

Xmethanol is the mole fraction of methanol,

P°methanol is the pure vapor pressure of methanol.

We need to calculate the mole fraction of methanol (Xmethanol).

Xmethanol = (n) methanol / (n) total.

where, n methanol is the no. of moles of methanol.

n total is the total no. of moles of methanol and urea.

We can calculate the no. of moles of both methanol and urea using the relation: n = mass/molar mass.

n of methanol = mass/molar mass = (56.9 g) / (32.04 g/mol) = 1.776 mol.

n of urea = mass/molar mass = (7.38 g) / (60.06 g/mol) = 0.123 mol.

∴ Xmethanol = (n) methanol / (n) total = (1.776 mol) / (1.776 mol + 0.123 mol) = 0.935.

∴ Psolution = (Xmethanol) (P°methanol) = (0.935) (89.0 mmHg) = 83.24 mmHg.

What is the vapor pressure at 20 °c of an ideal solution prepared by the addition of 7.38 g of the nonvolatile solute urea, co (nh2) 2, to 56.9 g of methanol, ch3oh? the vapor pressure of pure methanol at 20 °c is 89.0 mm hg.a. 5.75 mm hgb?

What is the vapor pressure at 20 °c of an ideal solution prepared by the addition of 7.38 g of the nonvolatile solute urea, co (nh2) 2, to 56.9 g of methanol, ch3oh? the vapor pressure of pure methanol at 20 °c is 89.0 mm hg.

a. 5.75 mm hg

b?