NATIONAL OPEN UNIVERSITY OF NIGERIA

UNIVERSITY VILLAGE, PLOT 91 CADASTRAL ZONE, NNAMDI AZIKIWE EXPRESS WAY, JABI – ABUJA.

FACULTY OF SCIENCES

DEPARTMENT OF PURE AND APPLIED SCIENCES

JULY 2018 EXAMINATION

 
COURSE CODE:       CHM 303
COURSE TITLE:        INORGANIC CHEMISTRY III
COURSE UNIT:         3
TIME:                            2 ⅟2 HOURS
INSTRUCTION:         Question one is compulsory. Answer question one and any other four questions.
QUESTION ONE
 
1ai) Mention the principal source of Ne, Ar and Xe and how these elements can be obtained from their source.                                                                                                                       3 mks
1aii) Write an equation representing the reaction between xenon and fluorine at 700k, 6 atm.
31/2 mks
1bi) Explain why Group IIIB elements, unlike group I and II are   essentially covalent or contain an appreciable amount of covalent character.                                                                   2 mks
1bii) Write short note on formation of complexes by transition metals.                          7 mks
1ci) Depending on chemical composition, classify minerals of metals.                           21/2 mks
1cii) Why is Carbon a preferred reducing agent in commercial metallurgy?                   2mks
1ciii) Carbon reduction is not used to obtain certain metals from their ores, explain      2 mks
 
QUESTION TWO
2ai) What kind of oxides is formed when oxygen reacts with;
-Group I and II metals
-Sulphur and Phosphorus                                                                                    2 mks
 
2aii)   How do the elements of Group IVA excluding carbon make more than four covalent bonds.                                                                                                                          2 mks
2bi)  Why are the compounds of Sc3+, Ti4+ and Zn2+ white or colourless.                 4mks
2bii)  Differentiate between gangue and slag.                                                            4 mks
 
QUESTION THREE
3ai) Explain the chemistry behind the steady increase in boiling points from He to Rn? 31/2 mks
3aii) State one characteristic and application of noble gases.                                               2mks
3bi) Complete the chemical equation for the reaction;
XeF2 + H2                                            2 mks
3bii)  Briefly explain the meaning and implication of lanthanide contraction. 41/2mks
 
QUESTION FOUR
4ai) Fill in the shapes of the following compounds.
 
Column I
Column II
XeF4
XeOF4
XeF4
XeF6
2 ½ mks
4aii) Using Valence Shell Electron Pair Repulsion Theory (VSEPR), justify the shape of XeF2   compounds.                                                                                                                        4 mks
4b) Comment on colour of transition metal compounds.                                                   5½mks
 
 
QUESTION FIVE
 
a)  Give reasons for the following:
Four reasons why beryllium is different from other members of group IIA.         4 mks
Why caesium is a more reducing agent than sodium.                                             2 mks
b)  Use the Valence Bond Theory to explain the formation of coordination compounds.  6 mks
 
QUESTION SIX
 
a)  Explain the chemistry behind beneficiation of ores.   4 mks
b)  Distinguish between the following methods of beneficiation of ores.
Gravity                                                                                                               4 mks
Magnetic separation                                                                                           4 mks
You can get the soft copy for this course or the exam summary answers for this course from 08039407882

Exam summary sample below

NATIONAL OPEN UNIVERSITY OF NIGERIA

UNIVERSITY VILLAGE, PLOT 91 CADASTRAL ZONE, NNAMDI AZIKIWE EXPRESS WAY, JABI – ABUJA.

FACULTY OF SCIENCES

DEPARTMENT OF PURE AND APPLIED SCIENCES

FEBRUARY/MARCH 2018 EXAMINATION

 
COURSE CODE:     CHM 303
COURSE TITLE:      INORGANIC CHEMISTRY III
TIME:                       2⅟2 HOURS
INSTRUCTION:         Question one is compulsory. Answer question one and
any other four questions.
 
QUESTION ONE
 
1ai) Discuss briefly why Group 1A elements are electropositive, and the trend of electropositivity among members of the group.41/2 marks
 
 
1aii) Complete this reaction:
 
 
 
XeF4 + Pt?2 marks
 
 
1aiii) Apart from oxygen other members of Group VI elements can make up to six covalent bonds, discuss.(2 marks)
 
1b) Comment on colour of transition metal compounds.91/2 marks
 
1ci) Depending on chemical composition, classify minerals of metals. (21/2 marks)
 
1cii) What are coordination compounds?(11/2 marks)
 
1ciii) Mention and explain the classes of coordination compounds.(3 marks)
.
QUESTION TWO
2ai) Discuss briefly the following:
i.                    The compound boron nitride
ii.                  Froth flotation process
iii.                Rare earth elements                                                                           15 marks
 
QUESTION THREE
3ai) Discuss the periodic trend in atomic radii among transition elements.             (4 marks
 
3aii) Distinguish between main group, transition and inner transition elements. (5marks)
 
3bi) Show with balanced chemical reaction the product formed when any nitrate of Group1A elements are heated. (2 marks)
 
3bii)Complete the following chemical equations.                                      (4 marks)
 
i.                    2K(s) + O2(g )
ii.                  2Na(s) + 2H2O
 
QUESTION FOUR
 
Write short note on the following methods of metal purification:
 
I.                   Electrolysis
II.                Zone refining
 
15 marks
 
QUESTION FIVE
5ai) Write on the following:
i.                    Four reasons why beryllium is different from other members of group IIA. (6 marks)
ii.                  Why caesium is a more reducing agent than sodium. (2marks)
 
5b) Describe formation of coordination compounds by Valence Bond Theory.(7 marks)
 
QUESTION SIX
 
6a) Write balanced chemical equations to show how reduction of iron oxide takes place in a blast furnace.                                                                          (6 marks)
 
6b) List and explain briefly the steps involved in processing of metals from their ores after extraction/mining. (9 marks)
You can get the soft copy for this course or the exam summary answers for this course from 08039407882

Exam summary sample below

NATIONAL OPEN UNIVERSITY OF NIGERIA

University Village, Plot 91 Cadastral Zone, NnamdiAzikiwe Express Way, Jabi – Abuja.

FACULTY OF SCIENCES

DEPARTMENT OF PURE AND APPLIED SCIENCES

JULY 2017 EXAMINATION

 
COURSE CODE:     CHM 303
COURSE TITLE:      INORGANIC CHEMISTRY III
COURSE UNIT:         3 Units
TIME:            2⅟2 HOURS
INSTRUCTION:         Question one is compulsory. Answer question one and any other four questions.
QUESTION ONE
1ai) Explain why the noble gases have very low melting and boiling points in comparison with those of other elements of comparable atomic or molecular weights.(3 marks)
 
1aii) What is the structure of the hydrides of carbon and silicon?(2 marks)
 
1aiii) Apart from oxygen other members of Group VI elements can make up to six covalent bonds, discuss.(2 marks)
 
1bi) Outline any three general properties of transition elements.(3 marks)
1bii) Write short note on formation of complexes by transition metals.(8 marks)
1ci) Depending on chemical composition, classify minerals of metals. (21/2 marks)
 
1cii) What are coordination compounds?(11/2 marks)
 
1ciii) Mention and explain the classes of coordination compounds.                       (3 marks)
QUESTION TWO
2ai) Why is there a steady increase in boiling points from He to Rn?(41/2 marks)
 
2aii) State one characteristic and application of noble gases. (2mark)
 
 
2bi) Complete this reaction XeF2 + H2.                                  (2 marks)
 
2bii)  Expatiate on the term “lanthanide contraction”    (61/2marks)
 
 
QUESTION THREE
3ai) Discuss the periodic trend in atomic radii among transition elements.             (4 marks
 
3aii) Distinguish between main group, transition and inner transition elements. (5marks)
 
3bi) Show with balanced chemical reaction the product formed when any nitrate of Group1A elements are heated. (2 marks)
 
3bii)Complete the following chemical equations.                                      (4 marks)
 
i.                    2K(s) + O2(g )
ii.                  2Na(s) + 2H2O
 
QUESTION FOUR
 
4a) Fill in the shapes of the following compounds.                                                (2 ½ marks)
 
Column I
Column II
XeF4
XeOF4
XeF4
XeF6
4aii) Using Valence Shell Electron Pair Repulsion Theory (VSEPR), justify the shape of XeF2 compounds. (6 marks)
 
4b) Comment on colour of transition metal compounds.                               (6½mark)
 
QUESTION FIVE
 
5ai) Write on the following:
i.           Four reasons why beryllium is different from other members of group IIA. (6 marks)
ii.          Why caesium is a more reducing agent than sodium. (2marks)
 
5b) Describe formation of coordination compounds by Valence Bond Theory.(7 marks)
 
QUESTION SIX
 
6a) Write balanced chemical equations to show how reduction of iron oxide takes place in a blast furnace.                                                                          (6 marks)
 
6b) List and explain briefly the steps involved in processing of metals from their ores after extraction/mining. (9 marks)
You can get the soft copy for this course or the exam summary answers for this course from 08039407882

Check exam summary sample below

NATIONAL OPEN UNIVERSITY OF NIGERIA

14/16 AHMADU BELLO WAY, VICTORIA ISLAND, LAGOS

SCHOOL OF SCIENCE AND TECHNOLOGY

MARCH/APRIL 2014 EXAMINATION

 
COURSE CODE: CHM 303
COURSE TITLE: INORGANIC CHEMISTRY III
TIME ALLOWED: 3 HOURS
INSTRUCTION: ANSWER ANY FIVE QUESTIONS
 
1ai. Briefly explain why XeF4 has square planar structure.2mks
ii. Juxtapose why vander waals force between the noble gas atoms increase down the group. 3mks
bi. Write short notes on the following;
i.                     Lambda point. 2mks
ii.                    Super conductivity. 2mks
iii.                  Radon. 2mk
c. Using chemical equations show the formation of Xenon Tetra fluoride.3mks
 
2ai. Write balanced chemical equations to describe the reaction of potassium metal with:
(i) oxygen      (ii) water      (iii) chlorine   (6 marks)
b. Work out the oxidation states of xenon in XeF4 and XeF6         (2mks)
c. Given below in Column I are the few expected compounds of noble gases. Write down in Column II the shapes of these compounds on the basis of VSEPR theory. (3mks)
Column I                                              Column                                                                 (i)   XeOF4                           (ii)    _____________________
(ii)   XeO4                                 (iii)    _____________________
(iii)   XeF6                                 (iii)  _______________________
d. State three State four uses of hydrogen. (3mks)
 
Question Three
3a. (i) List and describe the isotopes of hydrogen (3 marks)
(ii) What do you understand by the term ‘active hydrogen’? (2 marks)
b. Discuss the classification of ligands in coordination chemistry (6 marks)
Question Four
4ai. What are β rays? (2 marks)
b. Discuss briefly the principles of the valence bond theory (6 marks)
c. Highlight the differences between the valence bond and molecular orbital theories (6marks)
Question Five
5a (i) What is the difference between gangue and slag? (4 mks)
(ii) Write balanced chemical equations to show how the flux forms the slag in an iron blast furnace. (4 mks)
(b) (i) Why is it necessary to concentrate the ores before extracting metals from them?( 2 mks)
(ii) Describe the froth flotation process for the concentration of ores. (4mks)
Question Six
6ai. List and give the electronic configurations of the 3d transition elements (8 mks)
(b) What are rare earth elements? Why are they so called? (2 mks)
(c) (i) Identify the most common oxidation state for the lanthanides and the actinides (2 mks)
(ii) How is this oxidation state formed? (2 mks)
Question Seven
7ai. How do the following properties vary in the transition elements? (6 marks)
(i)         Atomic size
(ii)        Ionisation energy
(iii)       Electronegativity
 
(b) Highlight four characteristics of transition metals (4 mks)
(c) (i) Explain briefly why CuSO4 is blue while ZnSO4 is white (2 marks)
(ii) Predict the spin-only magnetic moment for: (2 marks)
Fe2+
You can get the soft copy for this course or the exam summary answers for this course from 08039407882

Check anoda sample below