Question

A sample of CaCl₂ weighing 7.45g is dissolved in 10.0mL of water, heated to 80°C then allowed to cool. It begins to crystallize (come out of solution as solid) when it reaches 20°C. Calculate the solubility of CaCl₂ in grams/100mL at 20°C 

Answer 1

mass dissolved = 7.45g

volume of water = 10.0mL

$\begin{aligned} CaCl_2 \textsf{ solubility }(g/100mL) &= \dfrac{mass(g)}{volume(mL)} × 100\\ \\ &=\dfrac{7.45}{10} × 100\\ \\ &= 74.5\ g/100mL\ at\ 20°C \end{aligned}$