Question

What is the molarity of a solution made when water is added to 11 g CaCl2 to make 100 mL of solution?

Answer 1

Molarity of a solution is defined as number of moles of solute dissolved per liter of solution.

Molarity ( M) = # of moles of solute / volume of solution (L)

Volume of Solution = 100 mL or 0.1 L

moles of Ca`Cl_2` = mass of Ca`Cl_2` / molar mass of Ca`Cl_2`

moles of Ca`Cl_2` = 11g / 111 g`mol^-1` = 0.099 mol

Molarity ( M) = # of moles of solute / volume of solution (L)

Molarity (M) = 0.099 mol / 0.1 L = 0.99mol/ L