The osmotic pressure of a 62.3mL solution is 0.862atm at a temperature of 34.0 oC. Calculate how many moles of the substance there are if the van't Hoff Factor is 2.49.
7.74 mol
7.74 x 10-3 mol
8.56 x 10-4 mol
8.56 x 10-1 mol
8.56 mol
To calculate the number of moles of the substance, we can use the formula for osmotic pressure:
π = iMRT
Where:
π = osmotic pressure
i = van't Hoff factor
M = molarity
R = ideal gas constant
T = temperature in Kelvin
First, we need to convert the temperature from Celsius to Kelvin:
T = 34.0 + 273.15 = 307.15 K
Since we're given the osmotic pressure (0.862 atm) and the volume of the solution (62.3 mL), we can rearrange the formula to solve for the molarity (M):
M = π / (iRT) = (0.862 atm) / (2.49 * 0.08206 L·atm/mol·K * 307.15 K)
M ≈ 0.00974 M
Now we can calculate the number of moles using the molarity and the volume:
moles = M * volume = (0.00974 mol/L) * (0.0623 L) ≈ 0.000606 mol
Thus, the correct answer is 7.74 x 10-4 mol.