Question

Five identical test tubes are each filled from the following five copper (II) sulfate stock solutions. Which of the following test tubes would appear the lightest blue?

A. Stock solution made form 0.200 moles of CuSO4 dissolved to a total volume of 400mL

B. Stock solution made form 0.150 moles of CuSO4 dissolved to a total volume of 300mL

C. Stock solution made form 0.250 moles of CuSO4 dissolved to a total volume of 500mL

D. Stock solution made form 0.175 moles of CuSO4 dissolved to a total volume of 400mL

E. Stock solution made form 0.125 moles of CuSO4 dissolved to a total volume of 300mL

Answer 1

find the concentration of each solution

The one with less concentration will be lightest

Concentration = number of mol / volume in L

A)

Concentration = number of mol / volume in L

= 0.200 moles/0.400 L

= 0.500 M

B)

Concentration = number of mol / volume in L

= 0.150 moles/0.300 L

= 0.500 M

C)

Concentration = number of mol / volume in L

= 0.250 moles/0.500 L

= 0.500 M

D)

Concentration = number of mol / volume in L

= 0.175 moles/0.400 L

= 0.4375 M

E)

Concentration = number of mol / volume in L

= 0.125 moles/0.300 L

= 0.417 M

E will be lightest

Answer: E