Question

select the correct answer. a 520 - gram sample of seawater contains 0.317 moles of nacl. what is the percent composition of nacl in the water? a. 1.1% b. 2.8% c. 3.6% d. 6.1%

Explanation:

Step1: Calculate mass of NaCl

Molar mass of \( \text{NaCl} \) is \( 58.44 \, \text{g/mol} \).
Mass of \( \text{NaCl} = \text{moles} \times \text{molar mass} = 0.317 \, \text{mol} \times 58.44 \, \text{g/mol} \approx 18.53 \, \text{g} \).

Step2: Calculate percent composition

Percent composition \( = \frac{\text{mass of NaCl}}{\text{mass of seawater}} \times 100\% = \frac{18.53 \, \text{g}}{520 \, \text{g}} \times 100\% \approx 3.56\% \approx 3.6\% \).

Answer:

C. 3.6%