Question

500 mL solution of calcium chloride with a concentration of 0.75 mol/L. The mass of solute needed to make this solution is ___ ___ ___ ___ g.

Answer 1

Answer:

41.63g

Explanation:

Given parameters:

Volume of CaCl₂  = 500mL  = 0.5L

Concentration  = 0.75mol/L

Unknown:

Mass of the solute needed = ?

Solution:

The mass of the solute can be derived using the expression below;

     Mass  = number of moles x molar mass

But,

   Number of moles  = Concentration x Volume

So;

     Mass  = Concentration x Volume x molar mas

Molar mass of CaCl₂  = 40 + 2(35.5) = 111g/mol

     Mass  = 0.75 x 0.5 x 111 = 41.63g