A solution is prepared by dissolving potassium fluoride (KF) in 347 g of water to make a 0.175 molal (m) KF solution. How many moles of KF are present in the solution?

• A. 0.175 moles
• B. 0.061 moles
• C. 2.0 moles
• D. 0.347 moles

Answer: (B)

Verified step by step guidance

1. Identify the definition of molality (m), which is the number of moles of solute per kilogram of solvent. The formula is: \(m = \frac{\text{moles of solute}}{\text{kilograms of solvent}}\).
2. Convert the mass of the solvent (water) from grams to kilograms by dividing by 1000: \(\text{mass of solvent in kg} = \frac{347}{1000}\).
3. Rearrange the molality formula to solve for moles of solute: \(\text{moles of solute} = m \times \text{mass of solvent in kg}\).
4. Substitute the given values into the rearranged formula: \(\text{moles of KF} = 0.175 \times \frac{347}{1000}\).
5. Calculate the product to find the number of moles of KF present in the solution.