A solution was prepared by dissolving 51.0 g of KBr in 310 mL of water. Calculate the mass percent of KBr in the solution.

• A. 16.4%
• B. 14.1%
• C. 19.7%
• D. 0.141%

Answer: (B)

Verified step by step guidance

1. First, calculate the mass of the solution. Since the density of water is approximately 1 g/mL, the mass of 310 mL of water is 310 g. Therefore, the total mass of the solution is the sum of the mass of KBr and the mass of water: 51.0 g + 310 g.
2. Next, determine the mass percent of KBr in the solution. The mass percent is calculated using the formula: \( \text{Mass percent} = \left( \frac{\text{mass of solute}}{\text{mass of solution}} \right) \times 100 \% \).
3. Substitute the known values into the formula: \( \text{Mass percent} = \left( \frac{51.0 \text{ g}}{\text{total mass of solution}} \right) \times 100 \% \).
4. Calculate the total mass of the solution by adding the mass of KBr and the mass of water: \( 51.0 \text{ g} + 310 \text{ g} = 361.0 \text{ g} \).
5. Finally, substitute the total mass of the solution into the mass percent formula to find the mass percent of KBr: \( \text{Mass percent} = \left( \frac{51.0}{361.0} \right) \times 100 \% \).