Which amount of calcium chloride would be needed to make a 1 molar solution in 1 L?

Which amount of calcium chloride would be needed to make a 1 molar solution in 1 L?

• A. 70.88 g calcium chloride plus water to make 1 L
• B. 110.96 g calcium chloride plus water to make 1 L
• C. 151.04 g calcium chloride plus water to make 1 L
• D. 221.92 g calcium chloride plus water to make 1 L

Answer: (B)

To make a 1 molar solution in 1 liter, you need 1 mole of calcium chloride for each liter. The molar mass of CaCl2 is about 110.98 g/mol (40.08 g for calcium plus 70.90 g for two chlorine atoms). So you’d dissolve roughly 110.98 g of CaCl2 in water to make 1 liter of 1 M solution. The option listed as 110.96 g is the closest to this value, which is why it’s the correct choice. The other masses would give you less than 1 mole, more than 1 mole, or 2 moles in 1 liter, respectively.

To make a 1 molar solution in 1 liter, you need 1 mole of calcium chloride for each liter. The molar mass of CaCl2 is about 110.98 g/mol (40.08 g for calcium plus 70.90 g for two chlorine atoms). So you’d dissolve roughly 110.98 g of CaCl2 in water to make 1 liter of 1 M solution. The option listed as 110.96 g is the closest to this value, which is why it’s the correct choice. The other masses would give you less than 1 mole, more than 1 mole, or 2 moles in 1 liter, respectively.