What is the molarity?

Question

A solution is 0.0500 m CsI. What is the molarity of the solution if the density is 1.10 g/mL?

Answer 1

m is molality and is defined as moles of solute per kg of solvent

M is molarity and is defined as moles of solute per liter of solution

Density is mass per volume and in this case = 1.10 g / ml.

Molar mass CsCl = 168 g / mol

0.0500 m CsCl = 0.0500 mols CsCl / kg water (assuming water is the solvent)

mass CsCl = 0.0500 mols x 168 g / mol = 8.4 g CsCl

Total mass of solution = 1000 g water + 8.4 g CsCl = 1008.4 g

Volume of solution = 1008.4 g x 1 ml / 1.10 g = 916.7 mls = 0.9167 L

Molarity of solution = mols / L = 0.0500 mols / 0.9167 L = 0.0545 M