Question

74.5 g of KCl was dissolved in 1000 mL of water. What is the molality of the solution? (Molar mass of KCl = 74.5 g/mol; Density of water = 1.00 g/mL)

a) 0.994 mol/kg
b) 0.012 mol/kg
c) 74.5 mol/kg
d) 0.074 mol/kg

Answer 1

To find the molality of the solution, divide the moles of solute by the kilograms of solvent.

Step-by-step explanation:

To find the molality of the solution, we need to calculate the moles of solute and the kilograms of solvent. Firstly, we convert the grams of KCl to moles by dividing by its molar mass: 74.5 g / 74.5 g/mol = 1 mol. Next, we convert the volume of water to kilograms by using its density: 1000 mL * (1 g/mL / 1000 g/kg) = 1 kg. Now, we can calculate the molality by dividing the moles of solute by the kilograms of solvent: 1 mol / 1 kg = 1.0 mol/kg.