What is the molarity of a solution that contains 20 grams of CaBr_2 dissolved in 0.50 L of solution?

• A. 0.20 M
• B. 0.20 M
• C. 0.20 mol
• D. 0.20 mol/L

Answer: (A)

Verified step by step guidance

1. Identify the given information: mass of CaBr_2 = 20 grams, volume of solution = 0.50 L.
2. Calculate the molar mass of CaBr_2 by adding the atomic masses of calcium (Ca) and bromine (Br). Use the formula: \(\text{Molar mass of CaBr}_2 = M_{Ca} + 2 \times M_{Br}\).
3. Convert the mass of CaBr_2 to moles using the formula: \(\text{moles} = \frac{\text{mass}}{\text{molar mass}}\).
4. Use the definition of molarity, which is moles of solute per liter of solution: \(M = \frac{\text{moles of solute}}{\text{volume of solution in liters}}\).
5. Substitute the moles of CaBr_2 and the volume of the solution into the molarity formula to find the molarity of the solution.