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ICH602S-INORGANIC CHEMISTRY-JAN 2020 |
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NAMIBIA UNIVERSITY
OF SCIENCE AND TECHNOLOGY
FACULTY OF HEALTH AND APPLIED SCIENCES
DEPARTMENT OF NATURAL AND APPLIED SCIENCES
QUALIFICATION: BACHELOR OF SCIENCE
QUALIFICATION CODE: 07BOSC
LEVEL: 6
COURSE NAME: INORGANIC CHEMISTRY | COURSE CODE: ICH602S
SESSION: JANUARY 2020
DURATION: 3 HOURS
PAPER: THEORY
MARKS: 100
SUPPLEMENTARY/SECOND OPPORTUNITY EXAMINATION QUESTION PAPER
EXAMINER(S) | DR EUODIA HESS
MODERATOR; | PROF HABAUKA KWAAMBWA
INSTRUCTIONS
Answer ALL the questions.
Write clearly and neatly.
Number the answers clearly.
All written work must be done in blue or black ink and sketches can
be done in pencil.
5. No books, notes and other additional aids are allowed.
PERMISSIBLE MATERIALS
Non-programmable Calculators
ATTACHMENTS
List of Useful Constants
Periodic Table
THIS QUESTION PAPER CONSISTS OF 8 PAGES (Including this front page, list of useful constants
and Periodic Table)
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SECTION A
[40]
QUESTION 1: Multiple Choice Questions
[40]
e There are 20 multiple choice questions in this section. Each question carries
2 marks.
e Answer ALL questions by selecting the letter of the correct answer.
e Choose the best possible answer for each question, even if you think there is
another possible answer that is not given.
1. How many electrons are there in the third shell (principal energy level) of the atom with
atomic number 23?
A. 11
B. 8
C.3
D. 10
2. How many electrons are there in the “p” orbitals of the last shell (principal energy level) of
silicon, atomic number 14?
A.4
B.3
C.0
D.2
3. Which of the following is the correct order for electrons filling in orbitals?
A. 2p, 3s, 3p, 3d
B. 3p, 4s, 3d, 5s
C. 1s, 2s, 2p, 2d
D. 3s, 3p, 4s, 3d
4. A lithium atom has an atomic number of 3 and a mass of 7. The number of electrons which it
has in the 1st shell (principal energy level) is
A.7
B.3
CG.
D.2
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5. When Li? 94 loses its single 2" shell (principal energy level) electron, its
electronic structure resembles that
A. Boron
B. Hydrogen
C. Helium
D. Neon
6. Bond created by overlapping of one modified orbit on another orbit is known as
A. Sigma bond
B. pi bond
C. Covalent bond
D. Dative bond
7. Molecular structure of SF is
A. octahedral
B. square planar
C. tetrahedral
D. trigonal bipyramidal
8. In Al2Cle, the number of electron pairs donated by each chloride ion are
A.1
B. 2
C.4
D.6
9. Number of bonding pairs of electrons in water H20 is
A.1
B.2
C.3
D.4
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10. What is the hybridisation of the carbon atoms in ethyne, C,H2?
A. sp
B. sp?
C. sp3
D. sp3d
11. What is the definition of an sp? hybrid orbital?
A. It contains one s atomic orbital and three p atomic orbitals.
B. It contains one-third s atomic orbital and two-thirds p atomic orbitals.
C. It contains one-fifth s atomic orbital and four-fifths p atomic orbitals.
D. It contains one-quarter s atomic orbital and three-quarters p atomic orbitals
12. What is the formal charge of the oxygen atom in H20?
A. +3
B. +1
C. -2
D. -3
13. What is the major attraction between water molecules in the solid physical state?
A. Dipole-dipole
B. Hydrogen bonds
C. Electrostatic attraction
D. Physical entanglement of molecules
14. Which of the bonds, shown by the dash, has the greatest polarity?
A. H-Cl
B. H-OH
C. H-SH
D. H-NH2
15. In which of the following compounds does ionic bonding predominate?
A. NH<Cl
B. LiBr
C. CHa
D. CO2
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16. lons which are produced from ligands are
A. Cations
B. Anions
C. Complex ions
D. All of them
17. In a face centred cubic lattice, the number of nearest neighbours for a given lattice point is
A.6
B.4
C.8
D. 12
18. The molecular geometry of S037 as predicted by VESPR theory is
A. bent
B. tetrahedral
C. square planar
D. triangular pyramidal
19. In a comparison with s-block elements, melting points of transition elements are
A. Higher
B. Lower
C. Same
D. Constant
20. Due to ligands' action of splitting colour of transition metal compound, this change occurs at
A. d-orbital
B. p-orbital
C. s -orbital
D. f-orbital
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SECTION B:
[60]
QUESTION 1:
[20]
1.1 Use the VSEPR model to predict the geometry of the following molecules and ions.
(10)
a) AsH3
b) OF2
c) AICl4
d) Ix
e) C2H4
1.2 Predict whether each of the following molecules has dipole moment and give an
explanation for each.
(6)
a) BrCl
b) BF3 (trigonal planar)
c) CH2Cl2 (tetrahedral)
1.3 Describe the hybridization state of phosphorus in PBrs.
(4)
QUESTION 2:
[10]
2.1 Which of the following can form hydrogen bonds in water and why?
(2)
CH30CH3; CHa; F; HCOOH; Nat
2.2 When silver crystallizes, it forms face-centered cubic cells. The unit cell edge length is
409 pm. Calculate the density of silver.
(8)
QUESTION 3:
[20]
3.1 Write the systematic names of the following coordination compounds:
(8)
a) Ni(CO)4
b) NaAuF,
c) Ka[Fe(CN)e]
d) [Cr(en)3]Cls
3.2 What are the geometries of the following two complexes?
(2)
a) [AICla]-
b) [Ag(NH3)2]*
3.3 Write the formula of each of the following coordination compounds:
(10)
a) Tetraammineplatinum(Il) chloride
b) Sodium hexacyanoferrate(III)
c) Tris(ethylenediamine)platinum(IV) sulfate
d) Diamminesilver(l) nitrate
e) Potassium diaquadioxalatocobaltate(II!)
QUESTION 4:
[10]
4.1 Calculate the amount of energy (in kJ) needed to heat 346 g of liquid water from O°C to
182°C. Assume that the specific heat of water is 4.184 J/g: °C over the entire liquid range
and that the specific heat of steam is 1.99 J/g: °C ( AHvap = 40.79 kJ/mol for water).
(5)
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4.2 Gold crystallizes in cubic close packed structure (fcc) and has a density of 19.3 g/cm’.
Calculate the atomic radius of gold in picometers.
(5)
END OF EXAMINATION
USEFUL CONSTANTS:
Gas constant, R = 8.3145 J -mol?: K*= 0.083145 dm?: bar: mol: K+= 0.08206 L atm mol?: K?
1Pa‘m?=1kPa.L =1N-'m =1)J
1 atm = 101 325 Pa = 760 mmHg = 760 torr
Avogadro’s Number, Na = 6.022 x 1023 mol
Planck’s constant, h = 6.626 x 104 Js
Speed of light, c = 2.998 x 108 ms*
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