Question

Calculate the molality of a solution prepared by dissolving 175 g of KNO3 in 750 g of water. (round to nearest hundreth)

Answer 1

We will get the molality from this formula:
Molality = no.of moles of solute / Kg of solvent 

So first we need the no.of moles of KNO3 = the mass of KNO3 / molar mass of KNO3
no.of moles of KNO3 = 175 / 101.01 = 1.73 mol
By substitution in the molality formula:
∴ molality = 1.73 / (750/1000) = 2.3 Molal

Answer 2

Answer:

2.31 molar

Explanation:

175 g/101 g/mol=1.73 mol

1.73mol/.750 L = 2.31 mol/L