Question

A compound is found to have a molar mass of 598 g/mol. If 35.8 mg of the
compound is dissolved in enough water to make 175 mL of solution at 25°C,
what is the osmotic pressure of the resulting solution?

Answer 1

Explanation:

Recall the formula for the osmotic pressure.

? = MRT

Where:

? = osmotic pressure

M = molarity

R = ideal gas constant

T = temperature

Convert mg to g, and mL to L.

35.8 mg * (1 g / 1000 mg) = 3.58 x 10^-2 g

175 mL * (1 L / 1000 mL) = 0.175 L

We're now ready to solve for the osmotic pressure.

? = ([n solute] / V solution L)RT

? = ([mass / molar mass] / V solution L)RT

? = ([3.58 x 10^-2 g / 598 g/mol] / 0.175 L)(0.0821Latm/molK)(298 K)

? = 8.37 x 10^-3 atm (Answer)