Question

20 g of calcium carbonate dissolve in 400 ml of water. calculate molarity and mole fraction of solute.

Answer 1

The problem gives you all the information you need in order to solve for the molality and mole fraction of the solution. In order to determine its molarity, you're going to need the solution's volume.

To get the volume, you have to know what the density of the solution is. Determine the percent concentration by mass of the solution first

%w/w

=

m

solute

m

solution

⋅

100

In your case, the mass of the solution will be

m

solution

=

m

glucose

+

m

water

m

solution

=

20

+

150

=

170 g

This means that you get

%w/w

=

20

g

170

g

⋅

100

=

11.8%