What is the concentration of a 0.700 M Na2SO4 solution expressed in g/mL?

• A. 0.070 g/mL
• B. 0.099 g/mL
• C. 0.200 g/mL
• D. 0.142 g/mL

Answer: (B)

Verified step by step guidance

1. Identify the given information: the molarity (M) of the Na2SO4 solution is 0.700 M, which means 0.700 moles of Na2SO4 per liter of solution.
2. Calculate the molar mass of Na2SO4 by adding the atomic masses of its elements: sodium (Na), sulfur (S), and oxygen (O). Use the formula: \(\text{Molar mass} = 2 \times M_{Na} + 1 \times M_{S} + 4 \times M_{O}\).
3. Convert the molarity to grams per liter by multiplying the molarity by the molar mass: \(\text{grams per liter} = 0.700 \text{ mol/L} \times \text{molar mass of Na}_2\text{SO}_4\).
4. Convert grams per liter to grams per milliliter by dividing by 1000, since 1 L = 1000 mL: \(\text{grams per mL} = \frac{\text{grams per liter}}{1000}\).
5. Express the final concentration in g/mL, which is the desired unit for the solution concentration.