Sch2103:Organic Chemistry Question Paper
Sch2103:Organic Chemistry
Course:Bachelor Of Crop Protection
Institution: Meru University Of Science And Technology question papers
Exam Year:2014
QUESTION ONE (30 MARKS)
(a) (i) What is organic chemistry? (1 Mark) (ii) What is the importance of organic chemistry in service to mankind? (1 Mark)
(b) Define the following terms (i) Catenation (ii) Chemical bond (2 Marks) (c) On combustion of 6.51mg of a compound X. 20.47mg of CO2 and 8.36mg of water were produced. The molecular weight of compound x was found to be 84. Calculate.
(i) The percentage composition of carbon and hydrogen. (2 Marks) (ii) The empirical formula (2 Marks) (iii) The molecular formula of the compound. (2 Marks)
(d) Draw the structure of methylcyclopentane
(e) Distinguish between (i) Homolysis and heterolysis (2 Marks) (ii) Isomers and isomerism (2 Marks)
(f) Write the structural formula for three compounds represents by the molecular formulae ??4??8??. (3 Marks)
2
(g) (i) Define the term hybridization (1 Mark) (ii) Indicate the type of hydridization for each of the Carbon atoms in the following compund
CH2 CH C C C
O
CH3
(h) Write the functional group of the following homologous series (i) Alkene (ii) Ketone (iii)Alkanol (iv) Alkanoic acid (4 Marks)
(i) Write a feasible reaction mechanism showing how methane reacts with chlorine. (3 Marks)
QUESTION TWO (20 MARKS)
(a) Distinguish between qualitative and quantitative elemental analysis. (2 Marks) (b) State two physical methods to test the purity of an organic compound. (2 Marks) (c) Describe a chemical test used to distinguish between saturated and unsaturated hydrocarbon. (4 Marks) (d) (I) Complete the following chemical equations (i) ??6??14 ? ??3??6+? (1 Mark)
(ii) ????3????2?????? ???? + ???????? ? ????2????3+? (1 Mark)
(II) Name the type of reactions represented by the reactions I above. (2 Marks)
(e) (i) What is an orbital (1 Mark) (ii) Draw the geometrical representation of 2S and 2P atomic orbital. (4 Marks)
(f) Show the bond polarity of C y bond in the following molecules. (i) ????3????2????
(ii) ????3????2????2
(iii)????3????2???? (3 Marks)
QUESTION THREE (20 MARKS)
(a) Distinguish between (i) Molecular and structural formula (2 Marks) (ii) Stereoisomerism and conformations
3
(b) Determine the partial negative charge on the Oxygen atom in a C = O bond. The bond length is 0 22.1 A and the bond dipole moment is D 3.2 (charge of an electron = 4.8 × 10-10??????) (3 Marks)
(c) Briefly describe using illustration the following: (i) ????3 hybridization (2 Marks) (ii) ????2 hybridization (2 Marks)
(d) Complete the following chemical reactions. (2 Marks) (i) ? ??? A HNaOHHC 2 52
(ii) 4 252 H CBOHHC ?? ?
(1 Mark)
(e) State Marko (1 Mark)
(f) Classify the following alcohols as primary, secondary and tertiary alcohols. (3 Marks) (i) ? ? ? ? OHCCH 33
(ii) OH CHCH 2 3 (iii) ? ? 3 3 CH OHCHCH
(g) Explain the following observations (i) Ethanol has higher boiling point than ethane (ii) Hexane has higher boiling point than butane (3 Marks)
QUESTION FOUR (20 MARKS)
(a) Given IUPAC systematic name for each of the following compounds
i) CH3CH2C(CH3)3
4
CH3 CH2 CH CH2 C
CH3
CH3
CH3
CH3
CH3 CH CH CH3
Cl
Br
CH2CH3H 3C
CH2 CH2 CH2 CH2 CH3
C
H
C
CH3
HH 3C
(ii)
(iii)
(iv)
(v)
(vi)
(b) Distinguish between (i) Sigma (??) bond and pie ?? bond (3 Marks)
(ii) Polar and non polar covalent bond (2 Marks)
(c) Briefly, describe the steps involved in molecular diagnosis of an organic compound. (4 Marks)
(d) Complete the following reactions (i) ????3????2????2????????2 + ??????
??2??2
5
(ii) ????3????????????3 + ????2 ?
(iii)????3????????????2????3 + ?????? ? (3 Marks)
(e) Represent four conformations of 1, 2-dichloroethane. (2 Marks)
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