. 2. Calculate the amount of urea required to prepare 300 mL of an 8M solution.
ID: 885980 • Letter: #
Question
. 2. Calculate the amount of urea required to prepare 300 mL of an 8M solution. (MW of urea = 60.06 g/mol). Represent the amount both in g and mg.
3. How will you prepare 125 ml of a 2.5% (v/v) solution of Triton detergent from a stock of 75%? How do you check that your final concentration is correct?
4. How will you prepare 400 mL of a 7% (w/v) solution of sucrose? MW of sucrose = 342.3 g/mol. Assume that the density of the sucrose solution is 1.
5. How many grams of TRIS is required to prepare 150 ml of 7.5 mM TRIS buffer? (MW of TRIS= 121.14 g/mol) 6. How many millimoles and micromoles are present in 650 mL of a 4.8 M solution of sodium citrate? (MW of sodium citrate = 294.1 g/mol). Be sure to give the answer in millimoles and micromoles.
7. After a protein preparation, you ended with 500 µl of 15 mg/mL protein B. What is the total yield of the protein B. If the molecular weight of the protein B is 14307 Da, what is the molarity (M) of the protein at 15 mg/mL concentration?
8. How will you prepare 240 µl of a 1:6 dilution of a 25 mg/ml protein solution using a buffer for dilution? What is the concentration of the diluted protein solution?
9. While performing a protein concentration measurement, you had to dilute protein A two times serially as follows to measure with in the linear range of the spectrophotometer. 1) 1 µl of protein A with 9 µl buffer (this dilution is designated as protein A_1), 2) 2 µl protein A_1 with 18 µl buffer (this second dilution is designated as protein A_2). The concentration of protein A_2 is 0.75 mg/mL. What is the concentration of protein A? What is the dilution factor for protein A_2?
10. How much of each of the following components are needed to prepare 1 L of a buffer containing 50 mM TRIS pH 8, 500 mM NaCl, 1 mM DTT, and 10% (v/v) glycerol? Make sure to determine the amount of water to be added to make up the volume to 1L. The concentration of the stock solutions are as follows:
a. 1 M TRIS pH 8
b. 5 M NaCl
c. 1M DTT
d. 50% glycerol
Explanation / Answer
2. Molarity = w/mw*1000/v in ml
8 = (w/60.06)*(1000/300)
weight of urea required = 144.144 grams
3. 2.5%(v/v) means 2.5 ml of Triton detergent in 100 ml solution.
To prepare 125 ml Triton detergent solution = 125*2.5/100
= 3.125 ml
But stock is only contains 75%.
so that = 3.125*100/75 = 4.17 ml
take 4.17 ml of stock and dissolve it in water. and make the solution to 125 ml
AS it is soap .it is basic in nature.so that by titrating with acid
it is possible to check concentration.
4. 7%(w/v),means 7 grams in 100ml solution.
to prepare 400 ml of 7%(w/v) solution take 28 grams of sucrose and
dissolve in water and make up to 400 ml.
5. M = w/mw*(1000/V in ml)
7.5*10^(-3) = (w/121.14)*(1000/150)
w = weight of TRIS = 0.136 grams
6. No of moles = M*V = 4.8*0.65 = 3.12 mole
millimoles = 3.12*10^3 mM
micromoles = 3.12*10^6 micro M
7. Volume = 500*10^(-3) ml = 0.5 ml
mass of protein = 0.5*15 = 7.5 mg
Molarity = (7.5/14307)*(1000/0.5)
= 0.001048 M
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