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.
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 =
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.
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.