When 2.25 g of a nonelectrolyte solute is dissolved in 125 mL of water at 22 °C, the resulting solution exerts an osmotic pressure of 955 torr.
What is the molar concentration of the solution?
How many moles of solute are in the solution?
What is the molar mass of the solute?
pi = MRT.
You know pi, R, and T. Solve for molarity.
M = mols/L. Solve for mols.
mols = grams/molar mass. Solve for molar mass.
Remember pi is 955/760 = ? if you use R = 0.08206.
To find the molar concentration of the solution, you can use the formula:
Molar concentration (M) = moles of solute / volume of solution in liters
First, convert the given volume of the solution from milliliters (mL) to liters (L):
125 mL = 125/1000 L = 0.125 L
Next, use the formula for osmotic pressure:
Π = MRT
Where:
Π is the osmotic pressure in atm (atmospheres)
M is the molar concentration of the solution in mol/L (molarity)
R is the ideal gas constant (0.0821 L·atm/(mol·K))
T is the temperature in Kelvin (K)
In the given problem, the osmotic pressure is given as 955 torr, which needs to be converted to atm:
955 torr = 955/760 atm = 1.2566 atm
The temperature is given as 22 °C, so we need to convert it to Kelvin:
T in K = 22 + 273 = 295 K
Now, rearrange the osmotic pressure formula to solve for molar concentration:
M = Π / (RT)
M = 1.2566 atm / (0.0821 L·atm/(mol·K) * 295 K)
Calculating this expression will give you the molar concentration of the solution in mol/L.
To find the number of moles of solute in the solution, you can use the formula:
moles of solute = molar concentration * volume of solution in liters
Simply multiply the molar concentration (calculated in the previous step) by the volume of the solution in liters (0.125 L).
To calculate the molar mass of the solute, you need to use the formula:
molar mass = mass of solute / moles of solute
In this case, the mass of the solute is given as 2.25 g, and the moles of solute can be calculated using the formula mentioned earlier.