A 18.0 wt% solution of CaCl2 ( 110.98 g/mol) has a density of 1.165 g/mL. What is the mass, in milligrams, of a 20.0 mL solution of 18.0 wt% CaCl2 ?

Answer 1

1.165 g / ml x 20.0 ml = 23.3 g = mass of 20.0 ml of solution

Since this is18.0% by mass CaCl₂, the mass of CaCl₂ = 18% x 23.3 g = 4.194 g CaCl₂

Converting this to mg, we have 4.194 g x 1000 mg / g = 4194 mg = 4190 mg (3 sig.figs.)