if you have 0.5 grams of CaCl2 dissolved to make 15mL of solution, what is the molarity of the solution?

0.3M

Explanation:

Molarity of a solution is given by;

M=n/v

Where;

n = number of moles of solute = mass of solute / molar mass

v = volume of solution

n = mass of CaCl2 / molar mass of CaCl2

Mass of CaCl2 = 0.5

Molar mass of CaCl2 = 40 + (2*35.5)

= 111g/mol

n = 0.5/111 = 0.0045mol

volume, v = 15mL = 15/1000 L = 0.015L

Note that molarity is in mole per liter, hence we convert 15mL to L. 1mL=1/1000L

M = 0.0045/0.015

M=0.3mol/L

Therefore, the molarity of the solution is 0.3M