In: Chemistry
An aqueous solution contains 5.8% KBr by mass.
Calculate the molality of the solution.
Calculate mole fraction of the solution.
Please help
Given An aqueous solution contains 5.8% KBr by mass.
That means 5.8 g of KBr present in 100 mL(=0.1 L) of the solution
Molar mass of KBr = At.mass of K + At.mass of Br
= 39 + 80
= 119 g/mol
So number of moles of KBr , n = mass/molar mass
= 5.8 g / 119 (g/mol)
= 0.0487 mol
(a) Molarity , M = number of moles / Volume in L
= 0.0487 mol / 0.1 L
= 0.487 M
We cannot calculate the mole fraction of solution we calculate only the mole fraction of either solute or solvent