Question

A solution is prepared as described in Part A using solid CaCl2⋅2H2O and de-ionized water. Mass of weighing bottle and solid before transfer: 35.870 g Mass of weighing bottle and solid after transfer: 25.746 g Size of volumetric flask: 200.00 mL What is the concentration of this calcium chloride solution in g/L? [Note that the mass of the waters of hydration are not included in the solution concentation.]

You need to remove the mass of the waters of hydration

Answer 1

weighing bottle and solid before transfer: 35.870

Mass of weighing bottle and solid after transfer: 25.746 g

Net weight                                                      : 10.124 gm

Molar mass of CaCl2*2H2O is 147.0146 g/mol

Hence concentration   =   10.124 x 1000 /200 x 147.0146 = 0.34431 Mole