1. If an aqueous solution that is 0.15 M in HF has an osmotic pressure of 3.9 atm at 25oC, what is the percent ionization of HF at this concentration?

2. A mixture of 2 volatile liquids is said to be ideal if each component obeys Raoult’s Law:

Pi=XiPio

Two volatile liquids A (molar mass 100 g/mol) and B (molar mass 110 g/mol) form an ideal solution. At 55oC, A has a vapor pressure of 98 mm Hg and B has a vapor pressure of 42 mmHg. A solution is prepared by mixing equal masses of A and B.

Calculate the mole fraction of each component in the solution.

User Icon for DrBob222 DrBob222 answered
9 years ago

pi = iMRT

Solve for i (use 0.08206 for R).

Then effective M = i*0.15 = ?
Then HF ==> H^+ + F^-
(H^+)=(F^-) = x
(HF = 0.15-x
Then x+x+0.15-x = i*0.15
Solve for x = (H^+) and
%ion = (H^+)/0.15)*100 =

User Icon for DrBob222 DrBob222 answered
9 years ago

What's the problem with #2? Just take equal amount of A and B (it doesn't mattr how many g you take as long as the amounts are equal). Calculate X of each and from there solve for p of each. I can help you if you get stuck.

User Icon for Explain Bot Explain Bot answered
11 months ago

To answer these questions, we need to apply the concepts of osmotic pressure and Raoult's Law. Here's how you can approach each question:

1. To determine the percent ionization of HF, we can use the formula for osmotic pressure and the relationship between concentration and ionization. Here are the steps:

Step 1: Calculate the osmotic pressure using the formula π = MRT, where π is the osmotic pressure, M is the molarity, R is the ideal gas constant, and T is the temperature.

Given:
Molarity (M) = 0.15 M
Osmotic pressure (π) = 3.9 atm at 25°C = 3.9 × 0.987 atm (since 1 atm = 0.987 atm)

Step 2: Rearrange the formula to solve for the molarity (M), which gives M = π/(RT). Plug in the values to find the molarity.

Step 3: Calculate the concentration of the undissociated HF using the formula C_(undissociated) = M × (1 - α), where α is the degree of ionization or percent dissociation.

Step 4: Calculate the concentration of the dissociated ions using the formula C_(dissociated) = M × α.

Step 5: Use the equation for the percent ionization (PI) = (C_(dissociated) / M) × 100 to find the result.

2. To calculate the mole fraction of each component in the solution following Raoult's Law, you can use the formula Pi = Xi × Pio, where Pi is the partial vapor pressure, Xi is the mole fraction of component i, and Pio is the vapor pressure of component i in its pure state. Here's how you can proceed:

Step 1: Find the mole fraction of each component using the formula Xi = ni / n_total, where ni is the moles of component i and n_total is the total number of moles of both components.

Given:
Molar mass of A (MA) = 100 g/mol
Molar mass of B (MB) = 110 g/mol
Vapor pressure of A (Pio_A) = 98 mmHg
Vapor pressure of B (Pio_B) = 42 mmHg

Step 2: Calculate the number of moles of each component using the given masses and molar masses.

Step 3: Calculate the total number of moles by summing the moles of A and B.

Step 4: Calculate the mole fraction of A using Xi_A = na / n_total, where na is the moles of A.

Step 5: Calculate the mole fraction of B using Xi_B = nb / n_total, where nb is the moles of B.

I hope this helps! Let me know if you have any further questions.