ORGANIC CHEMISTRY
1. A compound Y reacts with bromine to form another compound whose formula is CH3CH2CHBrCHBrCH3. What is the formula and name of compound? 2MK [ P1, 1992]
Formula;
Name:
2. Part of the structure of the polymer, polyphenylethene is given below.
i) Draw the general structure of polyphenylethene. 1MK
ii) Draw the formula of the monomer from which it made.1MK
3. When p was mixed with ethanoic acid and a few drops of concentrated sulphuric acid added pleasant smelling liquid R was formed. P also reacted with sodium metal to produce gas s. (RMM of P=46).
i) To what class of compounds do the following belong? 1MK
P____________________ 1MK
R____________________ 1MK
ii) Name gas S__________________________ 1MK
iii) Write a possible structure of P IMK
iv) Write the equation of the reaction which produces gas S. IMK
v) Compound M and P belong to the same class of compounds; M has a relative formula mass of 102. Which of the compounds would be less soluble in water?
Explain. 2MK
vi) Complete the following equation 1MK [ P1, 1993]
CH3COOH + Na2CO3
4.
a) Write an equation to represent the polymerization of 1- chloropropene. [ 1 MK]
b) Name the polymer formed in (i) above. [1MK] [P1, 1993]
5.
a) Study the table below and answer the questions that follow
Formula of hydrocarbon
Boiling point K
C2H4
C3H6
C4H8
C5H10
C6H12
196.4
225.5
266.9
303.0
336.5
i) What is the name given to a series of organic compounds like the ones above? 1MK
ii) To what class of organic compounds like the ones above hydrocarbons belong? 1MK
iii) Select one of the hydrocarbons that would be a gas at room temperature (298K). Give a reason for your answer.2MK
iv) Give the formula of the seventh member of the above series. 1MK
v) What is the relationship between the boiling point and the RMM of the hydrocarbons in the above table? Explain your answer. 2MK
b) What would you observe if a few drops of potassium permanganate was reacted with any of the above hydrocarbons? Explain. 2MK
c) Study the flow chart below and answer the questions that follow.
Compound Z
Ethene
Alcohol X
H2SO4 (l) HCl
Heat, process Y
i) Write the formula of
Alcohol X; __________________________ 1MK
Compound Z; _________________ ______ 1MK
ii) Name process Y;______________________ 1MK [P1, 1993]
6. Propane and chlorine react as shown below.
CH3CH2CH3 + Cl2 CH3CH2CH2Cl + HCL
a) Name the type of reaction that takes place. 1MK
b) State the condition under which the reaction occurs.1MK [P1, 1994]
7. RCOO-Na+ and RC6H5SO3-Na represents two cleansing agents where R is a long hydrocarbon chain.
a) Write the formulae of the salts that would be formed when each of these cleansing agents is added to water containing calcium ions.1MK
b) Explain how the solubility of the two calcium salts affects the properties of the cleansing agents.2MK [ P1, 1994]
8. The general formula for a homologous series of organic compounds is CnH2n+1OH
a) Give the name and structure formula of the fourth member of this series. 2MK
b) Write an equation for the complete combustion of fourth member of this series. 1MK [P1, 1994]
9. In an experiment, soap solution was added to three separate samples of water. The table below shows the volume of soap solution required to form lather with 1000cc of each of the water samples before and after boiling.
Sample I
Sample II
Sample III
Volume of soap before water was boiled
27.0
3.0
10.6
Volume of soap after water was boiled
27.0
3.0
3.0
a) Which is likely to be soft?
Explain.2MK
b) Explain the change in the volume of soap solution used in sample III 1MK[P1, 1995]
10. Name one natural fibre. 1MK [ P1 1995]
11. Give one advantage of synthetic fibre over natural ones. 1MK [P1, 1995]
12. Study the table below and answer the questions that follow.
Alkane
Formula
Heat of combustion
Methane
Ethane
Propane
Butane
CH4
C2H6
C3H8
C4H10
-890
-1560
-2220
a)
b)
c)
a) Predict the heat of combustion of butane and write it on the space provided. 1MK
b) What do the sign of ∆Hc value indicate about combustion of alkanes?1MK [P1, 1995]
13. A compound C4H10O is oxidized by acidified potassium permanganate to form another compound C4H10O2. The same compound reacts with potassium to produce hydrogen gas.
a) Draw the structural formula and name compound C4H10O. 1MK
b) Write an equation for the reaction between potassium and compound C4H10O. 1MK [P1, 1995]
14. The table below gives information about the major constituent of crude oil. Study it and answer the questions that follow.
Constituent
Boiling point
Gases
Petrol
Kerosene
Diesel oil
Lubricating oil
Bitumen
Below 40
40-175
175-250
250-350
350-400
Above 400
i)
ii)
iii)
iv)
i) Which one of the constituent of crude oil has molecules with the highest number of carbon atoms? Explain. 2MK
ii) Name the process you would use to separate a mixture of petrol and diesel and explain how the separation takes place. 2MK
iii) Explain why the constituents of crude oil do not have a sharp boiling point.2MK
iv) Name one gas that is likely to be a constituent of crude oil and write its formula. 2MK
v) What condition would cause a poisonous to be formed when kerosene is burnt? Explain. 2MK [P1, B 1995]
15. The reaction of propane with chlorine gas gave a compound of formula C3H7Cl
a) What condition is necessary for the above reaction to take place? 1MK
b) Draw two structural formulae of the compound C3H7Cl.1MK [ P1, 1996]
16. Explain how a sample of CH3CH2CH2OH, could be distinguished from a sample of CH3COOH by means of a chemical reaction. 2MK [P1, 1996]
17. A compound whose structure is shown below is found in detergent. With reference to the structure explain how the detergent removes grease during washing. 2MK [P1, 1996]
18. A polymer has the following structure. A sample of this found to have a molecular mass of 5194. Determine the number of monomers in the polymer. 3MK [P1, 1996]
19. A mixture of pentane and pentanoic acid was shaken with 0.1M sodium hydroxide solution and let to separate as shown in the diagram below. Name the main layer W. Give a reason for your answer. 2MK [P1, 1996]
20.
a) Study the table below and answer the question that follow:
i) Which of the compound is solid at 10oC? Explain. 1MK
ii) Choose two compounds which are members of the same homologous series and explain the difference in their melting points.3MK
iii) The compound C3H8O is alcohol. How does the solubility in water differ from the solubility of C5H12? Explain. 2MK
b) Complete combustion of one mole of hydrocarbon produced four moles of carbon (iv) oxide and four moles of water only
i) Write the formula of the hydrocarbon 1MK
ii) Write the equation of the combustion reaction.1MK
c) In a reaction, an alcohol J was converted to Hex-1-ene.
i) Give the structure formula of the alcohol J 1MK
ii) Name the reagent and the condition necessary for the reaction in, c(i) above 1MK
Reagent; ______________________
Condition; _______________________
d) Compound K reacts with sodium hydroxide as shown below
HCOOH + NaOH HCOONa + H2O
i) What type of reaction is represented by the equation above? 1MK
ii) To what class of organic compounds does k belong?1MK [P1, 1996]
21. Complete the table below by inserting the missing information in the spaces provided
Name of polymer
Name of monomer
One use of the polymer
Polystyrene
Vinyl chloride
1.5MK [P1, 1997]
22. The structures shown below represent two cleansing agent A and B
A: R-COONa+ B: CH3 (CH2)11 - B- OSO3-Na+1.
Which cleansing agent would be more suitable for washing in water containing magnesium sulphate? Give a reason. 2MK [P1, 1997]
23. The empirical formula of a hydrocarbon is C2H3. The hydrocarbon has a molecular mass of 54.
a) Determine the molecular formula of the hydrocarbon.1MK
b) Draw the structural formula of the hydrocarbon.1MK
c) To which homologous series does the hydrocarbon belong?1MK [ P1, 1997]
24.
a) Give the names of the following compounds
i) CH3CH2CH2CH2OH;_______________________ 1MK
ii) CH3CH2COOH;___________________________1MK
iii) CH3COOCH2CH3; _________________________ 1MK
b) Study the information in the table below and answer the questions that follow
Number of carbon atoms per molecule
RMM of hydrocarbon
2
3
4
28
42
56
i) Write the general formula of the hydrocarbons in the table.1MK
ii) Predict the RMM of the hydrocarbon with 5 carbon atoms.1MK
iii) Determine the molecular formula of the hydrocarbon in (ii) above and draw its structural formula.2MK
c) Study the reaction scheme below and answer the questions that follow
i) Name the reagents used in:
Step I: ______________________________ 1MK
Step II: ______________________________1MK
Step IV: _____________________________1MK
ii) Write an equation for the complete combustion of ethyne. 1MK
iii) Explain one disadvantage of the continued use of items made from the compound in step III 1MK [ P1, B 1997]
25. Give one advantage and one disadvantage of petrol containing tetraethyl lead. 2MK [P1, 1998]
26. Draw the structural formula of
i) Ethanol [1MK]
ii) Propanoic acid[ 1MK]
iii) Give the name of the organic compound formed when ethanol and propanoic acid react in the presence of concentrated sulphuric acid.1MK [P1, 1998]
27. The formula given below represents a portion of a polymer. Give;
a) The name of the polymer.1MK
b) One disadvantage of continued use of this polymer.1MK [P1, 1998]
28. The column below was used to soften hard water.
i) Explain how the hard water was softened as it passes through the column. 1MK
ii) After some time the material in the column is not able to soften hard water. How can the material be activated? 1MK
iii) Give one advantage of using hard water for domestic purposes.1MK [P1, 1998]
29.
a) The following equations represent two different types of reactions
i) nC4H8(g) (C4H8)n(s)
ii) C2H6 (g) + Cl2 (g) C2H5Cl (l) + HCl
State the type of reaction represented by;
(i) ____________________________ 1MK
(ii) ____________________________ 1MK
b) The fermentation of glucose produces ethanol as shown in the equation below
C6H12O6 2CH3CH2OH + CO2.
The process produces about 10% ethanol by volume.
i) State how the concentration of ethanol produced could be increased. 1MK
ii) State and explain the observation that would be made if a piece of sodium metal; was added to a sample of ethanol in a beaker. 1MK
iii) Give two commercial uses of ethanol other than in the manufacture of alcoholic drinks. 2MK
c) The molecular formula of a hydrocarbon is C6H14. The hydrocarbon can be converted into two other hydrocarbons as shown in the equation below
C6H14 x + C3H6
i) Name and draw the possible structure of X. 1MK
ii) State and explain the observation that would be made is a few drops of bromine water was added to a sample of X. 1MK
iii) Write an equation for the complete combustion of C3H8.1MK [P 1, B 1998]
30. State the observations that would be made when a piece of sodium metal is placed in samples of; Pentane; 1MK
Pentanol; 1MK [P1, 1999]
31. State and explain one disadvantage of using hard water in a boiler. 2MK [P1, 1999]
32. Compound L reacts with hydrogen bromide to give another compound whose structure is CH3CH2CH2CHBrCH3.
Give the structural formula and name of compound L.
Write an equation for the reaction which takes place between ethyne and excess chlorine gas.2MK [P1, 1999]
33. One of the fuels associated with crude oil is natural gas. Name the main constituent of natural gas and write an equation for its complete combustion. 2MK [P1, 1999]
34. Bromine reacts with methane as shown below;
CH4 +Br2 CH3Br +HBr
a) What conditions are necessary for this reaction to occur?1MK
b) Identify the bonds which are broken and those that are formed.2MK [P1, 1999]
35.
a) When an organic compound Y reacted with aqueous sodium carbonate, it produces carbon (IV) oxide. Y reacts with propanol to form a sweet smelling compound Z whose formula is CH3CH2COOCH2CH2CH3. 1MK
i) Name and draw the structural formula of Y. 2MK
ii) What is the name of the group of compounds to which Z belong. IMK
b) In an experiment, excess ethanol was warmed with acidified potassium dichromate for about twenty minutes. State and explain the observation that was made at the end of the experiment. 2MK
c) The scheme below was used to prepare a cleansing agent. Study it and answer the questions that follow
Solution of cleansing agent
And an alcohol
Fat NaOH + Boil
Step I
Step II
Solid cleansing agent
i) What name is given to the type of cleansing agent prepared by the method shown in the scheme? 1MK
ii) Name one chemical substance added in step II. 1MK
iii) What is the purpose of adding the chemical substance named above?1MK
iv) Name one suitable substances that can be used in step I. 1MK
v) Explain how an aqueous solution of the cleansing agent removes oil from utensils during washing.2MK [P1, 1999]
36. In the presence of UV light, ethane gas undergoes substitution reaction with chlorine.
a) What is meant by the term substitution reaction? 1MK
b) Give the structural formula and name of the organic product when equal volumes of ethane and chlorine react together. 2MK [ P1, 2001]
37.
a) State one cause of temporary hardness of water.1MK
b) How does distillation remove water hardness?2MK [2001]
38.
a) In which homologous series do the following compounds belong?
i) CH3CCH;_________________ IMK
ii) CH3CH2COOH:_____________ 1MK
b) Raw rubber is heated with sulphur in the manufacture of natural rubber
i) What is the name given to the process? 1MK
ii) Why is the process necessary? 1MK
c) Study the scheme given below and answer the questions that follow
Propan-1-ol
Two products Potassium
I
A
Polymer C
Propene Br2/CCl4
II
Propane
Methane
Hydrocarbon
i) Write an equation for the reaction between propan-1-ol and potassium metal. 1MK
ii) Name the process I and II 2MK
I________________________ II_____________________________
iii) Identify the products A and B 2MK
iv) Name one catalyst used in process II 1MK
v) Draw the structural formula of the repeating unit in the polymer C. 1MK
d) State two industrial uses of methane. 2MK [P2, 2001]
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