Question

What is the molarity of a solution that is 7.00% by mass magnesium sulfate and has a density of 1.071 g/mL?

Answer 1

Answer:

0.623 M

Explanation:

Step 1: Given data

• Percent by mass (%m/m): 7.00 %

• Density of the solution (ρ): 1.071 g/mL

• Molar mass of magnesium sulfate: 120.37 g/mol

Step 2: Calculate the percent by volume (%m/v)

We will use the following expression.

$\%m/v = \%m/m \times \rho = 7.00\% \times 1.071g/mL = 7.50g\%mL$

Step 3: Calculate the molarity

7.50 g of magnesium sulfate are dissolved in 100 mL of the solution. The molarity is:

$M = \frac{7.50g}{120.37g/mol \times 0.100L } = 0.623 M$