How many liters of a 2.18 M solution can be prepared using 200.0 g of K_2S (potassium sulfide)?

• A. 0.42 L
• B. 0.66 L
• C. 2.18 L
• D. 1.05 L

Answer: (B)

Verified step by step guidance

1. First, calculate the molar mass of potassium sulfide (K_2S). Use the atomic masses: K = 39.10 g/mol and S = 32.07 g/mol. The molar mass is given by \(\text{Molar mass} = 2 \times 39.10 + 32.07\) g/mol.
2. Next, convert the given mass of K_2S (200.0 g) to moles using the formula \(\text{moles} = \frac{\text{mass}}{\text{molar mass}}\).
3. Use the molarity definition to relate moles and volume: \(M = \frac{\text{moles of solute}}{\text{liters of solution}}\). Rearrange this to find the volume: \(V = \frac{\text{moles}}{M}\).
4. Substitute the moles of K_2S calculated in step 2 and the molarity (2.18 M) into the volume formula to find the volume of solution that can be prepared.
5. Make sure your final volume is expressed in liters, as required by the problem.