Given 2L of a .2M solution, how much liquid must be added with the addition of .5 moles in order to maintain a constant molarity?
A. .4
B. .9
C. 2.5
D. 4.5
C
First, the number of moles or the original solution should be calculated.
The new number of moles is .4 + .5 = .9. The total number of moles, when divided by the new total volume, must still have a molarity of .2. Let x be the amount of liquid added.