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I need help with this problem: 1. Add 500 l of water to 5 eppendorf tubes labele

ID: 986472 • Letter: I

Question

I need help with this problem:

1. Add 500 l of water to 5 eppendorf tubes labeled 1-5.

2. Then add 500 l of 1 M HCL or 5 M NaOH solution to the tube that is labeled 1. Mix well. Then make a 1:2 dilution with the next 4 tubes(the concentration of HCL/NaOH becomes less and less). What is the concentration of HCL/NaOH in these tubes?

3. Label 5 new eppendorf tubes A-E, and add 900 l of cell culture medium to each of the tubes.

4. From tube number 1, add 100 l of HCL/NaOH solution to tube A. And then add 100 l of HCL/NaOH solution from tube number 2 to tube number B, and then the same from tube number 3 to tube number C, and from tube number 4 to tube number D, and from tube number 5 to tube number E. What is the concentration of HCL/NaOH in the the 5 different tubes?(The cell culture medium has a pH between 7 and 8)

Explanation / Answer

water in micro lt NaOH in micro lt Concentration M Cell culture in micro lt NaoH from Tube 1 to 5 Concentration M (NaOH taken) 10^5 Tube 1 500 500 0.0125 Tube A 900 100 2.5 Tube 2 500 250 0.0166 Tube B 900 100 3.32 Tube 3 500 125 0.005 Tube C 900 100 1 Tube 4 500 62.5 0.00277 Tube D 900 100 0.55 Tube 5 500 31.25 0.001471 Tube E 900 100 0.29