I. You find a stock solution in the refrigerator labeled, Sucrose 3.50 g/L. You
ID: 863777 • Letter: I
Question
I. You find a stock solution in the refrigerator labeled, Sucrose 3.50 g/L. You add 1 mL of this stock to 24 ML of water to make Solution A. You then take 20 ml, of Solution A and add it to 80 mL of water to make 100 mL of Solution B (i.e., you do a 1/5 dilution). What is the final concentration of sucrose in mg/mL (with three significant figures) of Solution B? The problem tells you that the sucrose stock solution = 3.50 g/L = ______________ mg/mL. Solution A is made by doing a 1/25 dilution of the stock solution, and Solution B is made by doing a 1/5 dilution of Solution A. What is the concentration (mg/mL.) of solution B? Show your work.Explanation / Answer
Hi,
The solution is simple
3.50 g/Lsucrose means 3.50 mg/mL i.e 3.50 x 1000 mg/ 1 X 1000 mL
1 mL of 3.50 mg/mL is diluted with 24 mL of water to make solution A
Therefore the concentration would become
C1V1= C2V2
1 mL X 3.50 mg/mL = C2 X 25mL
Therefore, C2 = 0.14 mg/mL i.e concentration of solution A is 0.14 mg/mL
Now, 20 mL of solution A is diluted with 80 mL of water to make solution B
Therefore the concentration would become
20 mL X 0.14mg/mL = 100 mL X C2
C2 = 0.028 mg/mL i. e concentration of solution B is 0.028 mg/mL