3. You are required to make 100 ml of a 10 M KCI solution using a previously pre
ID: 713705 • Letter: 3
Question
3. You are required to make 100 ml of a 10 M KCI solution using a previously prepared 1 X 10 M stock. Detail how you would go about this showing all calculations. 4. Calculate the volumes of stock Bovine Serum Albumin (BSA) and the volume of Milli-Q H20 required to give the following final concentrations of BSA: 0, 5, 10, 15, 20, 25 mg/ml. Note: the concentration of the stock BSAprovided toyous?5X 10° ghnl. The final volume for each BSA 'standard' (0, 5, 10, 15, etc.) should be 25 ml. Show all working out. You may find it easier presenting your results in the form of a table like this (don't forget the units!): Final [BSA 10 15 20 25 vol BSA stock vol Milli-O 5. You are instructed to combine 5 ml of Coomassie Brilliant Blue solution (stoclk concentration-3 X 10" M) with 10 ml of Milli-Q H2O and 5 ml of a 40% Sucrose solution. What will the final concentration of Coomassic Blue be in the new solution? -S Show all working out.ie N2 LA
Explanation / Answer
3) The concentration of stock KCl solution is 1*10-2 M. The prepared solution of KCl must have a concentration of 10-4 M.
Determine the dilution factor (DF) as DF = (concentration of stock solution)/(concentration of dilute solution) = (1*10-2 M)/(10-4 M) = 100.
We need to prepare 100 mL of 10-4 M KCl solution; the volume of 1*10-2 M stock solution required to prepare 100 mL of the dilute solution = (final volume of the dilute solution)/(DF) = (100 mL)/(100) = 1 mL.
Therefore, the solution is prepared by adding 1 mL of 1*10-2 M stock KCl in a 100 mL volumetric flask and making up to the mark with (100 – 1) mL = 99 mL water.
4) The concentration of the provided stock solution of BSA is 25*103 µg/mL = (25*103 µg/mL)*(1 g/1*106 µg)*(1*103 mg/1 g) = 25 mg/mL.
The standard solutions have concentrations 0, 5,10, 15, 20 and 25 mg/mL BSA.
Work with the second standard solution for example. Determine the DF as DF = (25 mg/mL)/(5 mg/mL) = 5.
The final volume of the standard solution is 25 mL; therefore, volume of 25*103 µg/mL stock BSA solution added = (25 mL)/(5) = 5 mL.
Thus, we shall add 5 mL of 25*103 µg/mL stock BSA solution in a 25 mL volumetric flask and dilute upto the mark with (25 – 5) mL = 20 mL Milli-Q H2O.
Fill in the table.
Final [BSA] (mg/mL)
5
10
15
20
25
Vol. BSA stock (mL)
5
10
15
20
25
Vol. Milli-Q (mL)
20
15
10
5
0
5) The total volume of the dilute solution is (5 + 10 + 5) mL = 20 mL.
We start with 5 mL of the stock Coomassie Brilliant Blue solution and dilute to 20 mL; the dilution factor (can be expressed in terms of volumes as well) is
DF = (volume of final solution)/(volume of stock solution) = (20 mL)/(5 mL) = 4.
The concentration of Coomassie Brilliant Blue solution in the dilute solution = (concentration of stock solution)/(DF) = (3*10-4 M)/(4) = 7.5*10-5 M (ans).
Final [BSA] (mg/mL)
5
10
15
20
25
Vol. BSA stock (mL)
5
10
15
20
25
Vol. Milli-Q (mL)
20
15
10
5
0
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