Question

You make two dilutions. You take 85.25 mL of the stock solution and dilute to 500.0 mL to make Solution #1. You then add 57.01 mL of Solution #1 to 41.87 mL of water to make Solution #2. Stock solution is 8.299×10-5 M. What is the concentration of the Solution #2 in terms of molarity?

Answer 1

Given that;

Stock solution is 8.299×10-5 M.

First we will make 85.25 mL of the stock solution as follows:

Take 85.25 mL of the stock solution in a flask and now dilute to 500.0 mL to make Solution #1.

M1V1= M2V2

Here M1=8.299×10-5 M, V1 = 85.25 mL

V2 = 500 mL M2= ?

M2 = M1V1/V2

M2 =8 .299×10-5 M * 85.25 mL / 500 mL

M2= 1.415*10^-5 M this is solution #1

You then add 57.01 mL of Solution #1 to 41.87 mL of water to make Solution #2.

M1V1= M2V2

Here M1=1.415×10-5 M, V1 = 57.01 mL

V2 = 41.87 mL M2= ?

M2 = M1V1/V2

M2 =1.415×10-5 M * 57.01 mL /41.87 mL

M2= 1.926*10^-5 M this is solution #2