General Chemistry Lab Question 4.16.20

Question

In lab you are asked to perform an experiment that requires 100.00 mL of a 0.350 M potassium chloride solution. All you have in the lab though is a 0.750 M potassium chloride solution. Explain (in detail) how you would make the required 100.00 mL of 0.350 M solution using all common lab equipment that you have used in lab.

Would you have to use a titration experiment?

Answer 1

Hey Duch! Thanks for your question.

Here, it's probably easiest to use the equation C1*V1 = C2*V2, where "C" stands for concentration and "V" stands for volume. You can rearrange the equation to read: V1 = (C2*V2)/C₁

If you want a final solution of 100mL and a concentration of 0.35M, plug those values in to the numerator on the right side of the equation. You know your initial concentration (C₁) is 0.75M, so you can plug that in too. From there, its just a simple calculation:

V₁ = (0.35M * 100mL) / 0.75M

V₁ = 46.67mL

So in your final solution, you'll need 46.67mL of stock KCl, and the rest (53.33mL) will be water.

Hope this helps!!