Question

A student obtains 100 mL of a 0.0002669 M solution of AgNO3. He labels this “solution #1.” He then pipets 5 mL of solution #1 into a 50 mL volumetric flask and dilutes to the mark with water. He labels this “solution #2.” He then pipets 10 mL of solution #1 into a 250 mL volumetric flask and dilutes to the mark with water. This is “solution #3.” Finally, the prepares “solution #4” by pipetting 17 mL of solution #3 into a 50 mL volumetric flask and dilutes to the mark with water. Draw relational pictures to illustrate the relationship between the original solution and all of the diluted solution that the student prepared. What is the concentration of silver nitrate in Solution #4?

Answer 1

Initial conc. of solution A: 0.0002669 M = 2.669 X 10^-4 M

Dilution factor for solution 2: final volume/aliquot volume = 50ml/5ml =10

conc. of solution 2:  2.669 X 10^-4 M/dilution factor =2.669 X 10^-4 M/10 = 2.669 X 10^-5 M

Dilution factor for solution 3: final volume/aliquot volume = 250ml/10ml =25

conc. of solution 3:  2.669 X 10^-4 M/dilution factor =2.669 X 10^-4 M/25 = 1.0676 X 10^-5 M

Dilution factor for solution 4: final volume/aliquot volume = 50ml/17ml =2.941

conc. of solution 4:   1.0676 X 10^-5 M/ 2.941 = 0.3630 x10^-5 M