CHM413 – ANALYTICAL CHEMISTRY 11 (2014)

NATIONAL OPEN UNIVERSITY OF NIGERIA

14/16 AHMADU BELLO WAY, VICTORIA ISLAND, LAGOS

SCHOOL OF SCIENCE AND TECHNOLOGY

MARCH/APRIL 2014 EXAMINATION

 
COURSE CODE: CHM413                            
COURSE TITLE: ANALYTICAL CHEMISTRY 11
TIME ALLOWED: 2HOURS
INSTRUCTION: Six questions to answer four(Each question carriers a total 17marks)
 
Question 1
a) Distinguish between random and systematic errors (7marks)
b) Define the following terms:
i) Random error ii)         Confidence limits  iii)         Accuracy                      iv)        Precision                       (2mark each; total of 10marks)
 
Question 2
The result of the concentration of zinc metal (mg/L) in soil of a waste dump is presented as follows:
178.0 125.68   100.50147.50   111.16    95.46  143.20    98.89
 
Calculate:

1. i) Mean (3marks)
2. ii) Median (4 marks)

iii) Standard deviation                                                                                                  (5 marks)

1. iv) The 95% confidence limits for the true mean. (5 marks)

 
Question 3

1. a) State two types of glass membrane electrode (5 marks)
2. b) A solution is 10^-3M in Cr₂O₇^-2 and 10^-2M inCr^3+. If the pH is 2.0, what is the potential of the half reaction?                                                                                                             (8marks)

 
Question 4

1. a) Discuss the factors that affect the conductance of electrolyte solutions. (8marks)
2. b) Differentiate between thin layer chromatography and column chromatography. (9marks)

 
Question 5
Write short notes on the following:

1. a) Electrochemical deposition b)         Particulate radiation       c) Electromagnetic radiation
2. d) Ion exchange techniques. (4mark each; total of 17marks)

Questions 6
a)State theKohlrausch law of independent migration of ions                           (3marks)

1. b) Briefly explain the two application of Kohlrausch law of independent migration of ions (5 marks)
2. c) For acetic acid (HAc), L^o = 390.6 ohm^-1 cm² mol^-1, while at a concentration of 0.003441 mol dm^-3, L = 27.19 ohm^-1 cm² mol^-1. What is the degree of disassociation, the concentration of each          species, and the equilibrium constant?                                                                       (9 marks)

You can get the exam summary answers for this course from 08039407882

Check the sample below