Question

A total dilution of 1000 was made using two separate steps. In the first step, 9.6 mL was placed into 48 mL. What volume from the first dilution was placed into 63 mL?

Answer 1

Initial concentration = C1 = C; concentartion after first dilution = C2

Initial volume V1 = 9.6 mL; volume after first dilution V2= 9.6 mL + 48 mL = 57.6 mL

C1V1 = C2V2

C2 = C1V1/V2 = 9.6C1/57.6 = 9.6C/57.6

Second dilution

initial concentration C1 = 9.6C/57.6; concentration after second dilution C2 = C/1000

Initial volume V1 = X; final volume V2 = (X + 63)

C1V1 = C2V2

V1 = C2V2/C1 = (C/1000) x (X + 63)/(9.6C/57.6)

X = (C/1000) x (X + 63)/(9.6C/57.6) = 0.38 mL