A compound is found to have a molar mass of 190 g mol^-1.If 0.0673 g of the compound is dissolved in enough water to make 200 mL of solution at 25 °C,what is the osmotic pressure of the resulting solution? A)1.21 × 10^-2 bar B)6.12 × 10^-2 bar C)4.39 × 10^-2 bar D)3.97 × 10^-2 bar E)2.28 × 10^-2 bar

Question

Quizplus · Accepted Answer

First, we need to find the number of moles of the compound present in 0.0673 g by dividing it by the molar mass:
n = 0.0673 g / 190 g mol⁻¹ = 3.54 × 10⁻⁴ mol
Next, we need to convert the volume of the solution from mL to L and calculate the concentration in mol L⁻¹:
C = n / V = 3.54 × 10⁻⁴ mol / 0.2 L = 1.77 × 10⁻³ mol L⁻¹
Finally, we can use the Van't Hoff factor (i) of the compound, which depends on its dissociation behavior, to calculate the osmotic pressure using the formula:
π = iMRT
Here, we assume that the compound is non-dissociating, so i = 1. The gas constant R is 0.0831 L bar K⁻¹ mol⁻¹, and the temperature T is 25 °C or 298 K. Therefore:
π = MRT = CRT = (1.77 × 10⁻³ mol L⁻¹) (0.0831 L bar K⁻¹ mol⁻¹) (298 K) = 0.447 bar
which is equivalent to 4.39 × 10⁻² atm or 4.32 × 10⁻² atm. 
Rounding to the nearest 0.01 bar gives the answer of C, 4.39 × 10⁻² bar.

A Compound Is Found to Have a Molar Mass of 190