Question

A chemist makes up a solution by dissolving 42.0 g of Mg(NO3)2 in enough water to produce a final solution volume of 259 mL. To calculate the molarity of the solution, what additional information is needed?

Answer 1

Answer:

The molar mass of Mg(NO₃)₂, 148.3 g/mol.

Explanation:

Step 1: Given data

• Mass of Mg(NO₃)₂ (solute): 42.0 g

• Volume of solution: 259 mL = 0.259 L

Step 2: Calculate the moles of solute

To calculate the moles of solute, we need to know the molar mass of Mg(NO₃)₂, 148.3 g/mol.

42.0 g × 1 mol/148.3 g = 0.283 mol

Step 3: Calculate the molarity of the solution

M = moles of solute / liters of solution

M = 0.283 mol / 0.259 L

M = 1.09 M