Question

Starting with 0.1250 M Cu(NH3)2+ as the stock (concentrated) solution, calulate the concentrations of each of the following dilute solutions (show your work):

a. 15.0 ml of the stock solution diluted to 20.0ml

b. 10.0 ml of the stock solution diluted to 20.0ml

c. 5.0ml of the stock solution diluted to 20.0 ml

Answer 1

use dilution formula

M1*V1 = M2*V2

Here:

M1 is molarity of solution before dilution

M2 is molarity of solution after dilution

V1 is volume of solution before dilution

V2 is volume of solution after dilution

a)

we have:

M1 = 0.125 M

V1 = 15.0 mL

V2 = 20.0 mL

we have below equation to be used:

M1*V1 = M2*V2

M2 = (M1*V1)/V2

M2 = (0.125*15)/20

M2 = 0.0938 M

Answer: 0.0938 M

b)

we have:

M1 = 0.125 M

V1 = 10.0 mL

V2 = 20.0 mL

we have below equation to be used:

M1*V1 = M2*V2

M2 = (M1*V1)/V2

M2 = (0.125*10)/20

M2 = 0.0625 M

Answer: 0.0625 M

c)

we have:

M1 = 0.125 M

V1 = 5.0 mL

V2 = 20.0 mL

we have below equation to be used:

M1*V1 = M2*V2

M2 = (M1*V1)/V2

M2 = (0.125*5)/20

M2 = 0.0312 M

Answer: 0.0312 M