Question

A chemist needs to create a series of standard Cu2+(aq) solutions for an absorbance experiment. For the first standard, he uses a pipet to transfer 10.00 mL of a 2.61 M Cu2+(aq) stock solution to a 250.0 mL volumetric flask, and he adds enough water to dilute to the mark. He then uses a second pipet to transfer 10.00 mL of the second solution to a 100.0 mL volumetric flask, and he adds enough water to dilute to the mark. Calculate the concentration of the Cu2+(aq) solution in the 100.0 mL volumetric flask. concentration: M

Answer 1

0.01 M

Step-by-step explanation:

The chemist is performing a serial dilution in order tyo obtain the calibration curve for the instrument.

First we must obtain the concentration of the solution in the 250ml flask from

C1V1 = C2V2

Where;

C1 = concentration of the stock solution

V1 = volume of the stock solution

C2 = concentration of the diluted solution

V2= volume of the diluted solution

2.61 × 10 = C2 × 250

C2 = 2.61 × 10/250

C2 = 0.1 M

Hence for solution in 100ml flask;

0.1 × 10 = C2 × 100

C2 = 0.1 × 10/100

C2 = 0.01 M