solubility chemistry?

Question

The solubility of calcium chloride in water at 20degreesC is 26.7g/100mL. Calculate its molarity.

Answer 1

MW CaCl2 = 111 g/mole

26.7 g/111 g/mol = 0.241 moles

0.241 moles / 0.100 L = 2.41 M

Answer 2

CaCl2 --> Ca2+ + 2Cl-
-s +s +2s

K= (s^2)(2s)^2
K= 4s^3
where s= 26.7 g/ 100mL

1. convert 26.7 g to moles
(26.7 g)(1 mole/ 110.986 g)= 0.2406 mole

2. convert 100 mL to L
(100 mL) (1 L/ 1000 mL)= 0.100 L

3. divide mole by liter volume to get molarity
.2406 mole / 0.100 L = 2.406 mole/ L or 2.406 M

4. fix sigfigs
2.41 M

Therefore, CaCl2's molarity is 2.41 M

Answer 3

So you start with 100g of KNO3 in solution. When you cool that solution only 38g will be able to stay in solution, so the rest will crystallize out. so: 100-38=62g crystallized out.