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

• A. 13.8 g
• B. 55.5 g
• C. 11.1 g
• D. 27.5 g

Answer: (D)

Verified step by step guidance

1. Identify the given information: volume of solution = 250 mL, molarity (M) of CaCl_2 = 2.0 M. Remember to convert volume from milliliters to liters because molarity is in moles per liter.
2. Convert the volume from milliliters to liters using the conversion factor: \$1\, \text{L} = 1000\, \text{mL}\(. So, \)250\, \text{mL} = \frac{250}{1000} = 0.250\, \text{L}$.
3. Calculate the number of moles of CaCl_2 in the solution using the molarity formula: \(\text{moles} = M \times \text{volume in liters}\). Substitute the values to find moles of CaCl_2.
4. Find the molar mass of CaCl_2 by adding the atomic masses of calcium (Ca) and chlorine (Cl). Calcium has an atomic mass of approximately 40.08 g/mol, and chlorine has an atomic mass of approximately 35.45 g/mol. Since there are two chlorine atoms, multiply chlorine's atomic mass by 2 and add to calcium's atomic mass.
5. Calculate the mass of CaCl_2 by multiplying the number of moles by the molar mass: \(\text{mass} = \text{moles} \times \text{molar mass}\). This will give the mass of CaCl_2 in grams present in 250 mL of the solution.