Question

Suppose that a solution is prepared by mixing 25 mL (0.22 mol, 16 g) of pentane (the solute) with 45 mL (0.34 mol, 30 g) of hexane (the solvent). If the volumes add on mixing.

Calculate the molality of the pentane

[1] 3.1 mol/kg

[2] 4.8 mol/kg

[3] 7.3 mol/kg

[4] 3.1 mol/L

[5] 7.3 mol/L 

Answer 1

$c=0.22x1000/(16+30)=4.8 mol/kg$

Answer: [2] 4.8 mol/kg