Calculate the molality of a 0.425 molar aqueous solution of KOH having a
density of 1.13 g/mL.
To calculate the molality of a solution, we need to first convert the density of the solution to kg/mL.
Given: density = 1.13 g/mL
To convert the density to kg/mL:
1 kg = 1000 g
1 mL = 1 cm³
density(kg/mL) = density(g/mL) / 1000
density(kg/mL) = 1.13 g/mL / 1000 = 0.00113 kg/mL
Now we can calculate the molality using the formula:
molality = moles of solute / mass of solvent in kg
Moles of solute (KOH) is given as 0.425 moles per liter (molar). So, for 1 liter of solution, we have 0.425 moles of KOH.
Mass of solvent = density x volume of solution
volume of solution = 1 L = 1000 mL
mass of solvent = density x volume of solution = 0.00113 kg/mL x 1000 mL = 1.13 kg
Now, we can calculate the molality:
molality = 0.425 moles / 1.13 kg = 0.376 mol/kg
Therefore, the molality of the 0.425 molar aqueous solution of KOH is approximately 0.376 mol/kg.