SECTION B
QUESTION 3
Enumerate the following. Please include all working in your answer.
MW: Na - 23, 0 - 16, Cl - 35.5, H - 1, C - 12
[35]
[20]
3.1 The analyte concentration in a sample is 1500 mg/dl. The sample was
diluted in a series as follows (table 1):
Table 1. Sample dilution protocol
Tube#
Tube 1
Tube 2
Tube 3
Tube 4
Tube 5
Dilution
1:5
1:2
1:4
1:5
1:10
3.1.1 What is the dilution factor in the final tube (tube 5)?
(2)
3.1.2 What is the concentration of sample in each tube?
(10)
3.2 How do you prepare 775ml of a 0.5% (w/v) solution of NaOH?
(2)
3.3 You need to make a 1:5 dilution of a solution. You need 10 ml of the
(2)
diluted solution. How much initial sample and diluent should you use?
3.4 If I leave 750 ml of 0.50 M NaCl solution uncovered on a windowsill and
(2)
150 ml of the solvent evaporates, what will the new concentration of the
NaCl solution be?
3.5 If I have 340 ml of a 0.5 M HCI solution, what will the concentration be if I (2)
add 560 ml more water to it?
QUESTION 4
[15]
Presented below are the results of daily quality control for serum amylase
measurement (figure 1). The control range is 60-90U/l (+/- 25D).
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