OPEN BOOK TEST - 2 ESSENTIAL SKILLS IN SCIENCE

Today, second open book test was conducted. I have observed that all students attend such tests. We should try this. Next week assessment test of this course of 100 marks will be conducted. The test paper was like this.
 

Molecules and Moles

Use scientific notation whenever appropriate.

(E.g., write 2.3 x 10 -9 instead of 0.0000000023)

1.         Calculate the number of mols of glucose in:

            (a)  700 ml of 1 nM solution 

            (b)  0.25 ml of 10 M solution

            (c)  2.5 ml of 3 x 10-5 M solution

(d)   30 µl of 0.02 M solution  

2.  Express 10 mM in units of:

(a)  mmol / litre                       (b)  µmol /  µl                  

(c)  mmol /  µl                         (d)  mmol / ml             

(e)   µmol / ml                         (f)   nmol / µl 

3 Calculate the molarity of a solution containing:

(a)  65 mg of bovine serum albumin per ml (Mr of bovine serum albumin = 65,000)

(b)  12 mg NaOH/5 ml   (Mr NaOH = 40)  

(c)  74 mg KCl/100 ml   (Mr KCl = 74).  

4 (a) Equal volumes of solution A and water were mixed and then a 0.1 ml sample of the mixture was shown to contain 0.2 mg of solute P. 

            What was the concentration of P in solution A (in mg/ml)?

(b)  Enough acid was added to 0.5 ml of solution A to dilute the latter 10-fold and then a 2 ml sample of the mixture was shown to contain solute R at a concentration of 2 mM.

How many µmol of R were there in the original 0.5 ml sample of solution A (in µmol)?

Q5. 5ml of cell homogenate was prepared. A 0.1ml sample was mixed with 4.9 ml of water and was shown to contain 0.25mM of sucrose.  1ml of this was mixed with 4ml of Trichloroacetic acid. The resulting precipitate was solubilised in 2ml and was shown to contain 1ng/ml protein.

(a)    What was the concentration of sucrose in the original sample (in mM)?

                                                                                                  

      (b) How many moles of sucrose was present in the original sample (in

 Moles)?

      (c) What is the protein concentration in the original sample?