Question

Calculate the molarity of a solution made by dissolving 3.0 g of calcium chloride (CaCl2) in enough water to make 300 mL of solution.

A) 0.2 M
B) 0.4 M
C) 0.6 M
D) 0.8 M

Answer 1

The molarity of a solution made by dissolving 3.0 g of CaCl2 in 300 mL of water is 0.09 M, which is calculated by first finding the number of moles of CaCl2 and then dividing by the volume of the solution in liters.

Step-by-step explanation:

To calculate the molarity of a solution made by dissolving 3.0 g of calcium chloride (CaCl2) in enough water to make 300 mL of solution, you must first calculate the number of moles of CaCl2 that the 3.0 g represents. Calcium chloride has a molar mass of approximately 110.98 g/mol, so:

• 3.0 g CaCl2 ÷ 110.98 g/mol = 0.027 moles of CaCl2
• Then, convert the solution volume from mL to L; 300 mL = 0.300 L
• Molarity (M) = moles of solute (n) ÷ liters of solution (L)
• 0.027 moles ÷ 0.300 L = 0.09 M

Thus, the molarity of the solution is 0.09 M. This answer is not listed amongst the options, so there may have been an error in the question or the provided options.