A solution contains 34.2 grams and is 45.5% by mass NaF. How many moles of NaF are present in the solution?

• A. 0.370 moles
• B. 0.410 moles
• C. 0.520 moles
• D. 0.210 moles

Answer: (A)

Verified step by step guidance

1. Identify the given information: the total mass of the solution is 34.2 grams, and the solution is 45.5% by mass NaF.
2. Calculate the mass of NaF in the solution using the percentage by mass: \(\text{mass of NaF} = \frac{45.5}{100} \times 34.2\) grams.
3. Find the molar mass of NaF by adding the atomic masses of sodium (Na) and fluorine (F): \(\text{molar mass of NaF} = \text{atomic mass of Na} + \text{atomic mass of F}\).
4. Calculate the number of moles of NaF using the formula: \(\text{moles of NaF} = \frac{\text{mass of NaF}}{\text{molar mass of NaF}}\).
5. Use the calculated moles to select the correct answer from the given options.