How many grams of CaCl_2 are present in 250 mL of a 2.0 M CaCl_2 solution?

• A. 5.5 g
• B. 27.5 g
• C. 55.5 g
• D. 11.1 g

Answer: (B)

Verified step by step guidance

1. Identify the given information: volume of solution = 250 mL, molarity (M) of CaCl_2 = 2.0 M.
2. Convert the volume from milliliters to liters because molarity is expressed in moles per liter: \(\text{Volume (L)} = \frac{250}{1000} = 0.250\) L.
3. Use the molarity definition to find the number of moles of CaCl_2: \(\text{moles} = M \times \text{Volume (L)} = 2.0 \times 0.250\).
4. Calculate the molar mass of CaCl_2 by adding the atomic masses: Ca (40.08 g/mol) + 2 × Cl (35.45 g/mol) = \$40.08 + 2 \times 35.45$ g/mol.
5. Multiply the moles of CaCl_2 by its molar mass to find the mass in grams: \(\text{mass} = \text{moles} \times \text{molar mass}\).