1) 60 g of water was used to dissolve 35.79 g of CaCl₂.
2) The weight of a dry 50 mL volumetric flask was 59.62 g.
3) The flask was filled with the obtained CaCl₂ solution till the graduation mark. The weight of the filled flask was 127.85 g.
4) The CaCl₂ solution was poured from the volumetric flask into a beaker and diluted with 100 g of water. The volumetric flask was filled with the new solution. The weight of the filled flask was 118.66 g.
5) After the next dilution as in step 4, the weight of the filled flask was 114.11 g
6) After one more dilution, the weight of the filled flask was 111.83 g.
Calculate:
a) the molality (m, mol/kg solvent) of the four solutions;
b) volumes of the solutions containing 1kg H₂O and having molality m;
c) build a graph in coordinates of m versus V and fit it to a quadratic polynomial:
V = a∙m² + b∙m + c
d) Take the derivative of the equation above to obtain the function for the partial molar volume of CaCl₂:
V̅(CaCl₂) = 2∙a∙m + b