The molecular weight of CaCl2 is 110.98 g/mol. In order to make up 500. mL of a 0.500 M solution, you need:

a)55.6 g
b)27.7 g
c)222.2 g
d)111.1 g
e)34.4 g

Question

The molecular weight of CaCl2 is 110.98 g/mol. In order to make up 500. mL of a 0.500 M solution, you need:

a)55.6 g
b)27.7 g
c)222.2 g
d)111.1 g
e)34.4 g

jfraser · Answer

Concentration in terms of M is (moles/L). When a solution is made, the moles of solute and total volume of the solution determine its concentration. Since $$C = mol/L$$ then $$mol = C * L$$ the moles of solute will be the product of the concentration and volume.$$mol = (0.5M)*(0.5L) = 0.25mol solute$$
so 0.25moles of CaCl2 will have to be dissolved into 500mL (0.5L) of solution.
Use the molar mass of CaCl2 to find the grams needed

anonymous · Answer

So which is it?