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Form 5 Chapter 2
ANALYSIS OF PAST YEAR QUESTIONS FROM 2003 - 2008
Year
2003
Paper No.
P2
Type of
question
S
Question No
4
2004
P3
E
S
P2
E
2005
P3
S
E
6
2
S
P2
E
S
2006
P3
E
S
P2
E
S
2007
P3
E
S
P2
E
S
3
2008
P3
E
9
S
P2
E
S
4
P3
E
S
E
1
STRUCTURED QUESTIONS
1
SPM 2003/P2/Q4
Figure 4 shows the set-up of apparatus for the preparation of ethyl ethanoate from the
reaction of ethanol with ethanoic acid.
(a)
On the Liebig condenser in Figure 4, mark ‘X’ to indicate the place where water flows
in and ‘Y’ where water flows out.
[1 mark]
(b)
Why is the mixture heated using a water bath?
……………………………………………………………………………………………………
……………………………………………………………………………………………………
[2 marks]
(i) Name the reaction for the preparation of ethyl ethanoate.
…………………………………………………………………………………………………….
[1 mark]
(ii) Write the chemical equation for the reaction in (c)(i).
(c)
…………………………………………………………………………………………………….
[1 mark]
The experiment is repeated by replacing ethanol with propanol
.
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Form 5 Chapter 2
(i) Name the ester formed.
……………………………………………………………………………………………………
[1 mark]
(ii) State one physical property of the ester.
……………………………………………………………………………………………………
[1 mark]
(d)
The flow chart below shows the conversion of ethanol to ethane and ethanol to
ethanoic acid.
Based on the flow chart, write the chemical equation for
(e)
(i) Process I.
…………………………………………………………………………………………………..
[1 mark]
(ii) Process II
(f)
……………………………………………………………………………………………………
[1 mark]
An alkene has a structural formula as shown below
What is the name of the alkane?
…………………………………………………………………………………………………….
[1 mark]
2
SPM 2004/P2/Q6
Figure 6 shows the reaction in the preparation of margarine.
(a)
(i) Name the process used to produce margarine in Figure 6.
…………………………………………………………………………………………
[1 mark]
(ii) State one effect of this process on the vegetable oil.
……..…………………………………………………………………………………
[1 mark
]
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(b)
Form 5 Chapter 2
(i) Name catalyst X and state the range of temperature Y in the production of
margarine.
Catalyst X: …………………………………………
Temperature Y: ………………………………........ oC.
[2 marks]
[Concept based on Chapter 1: Rate of reaction]
(ii) Based on the collision theory, explain the effect of catalyst X and temperature Y
in the production of margarine.
…………………………………………………………………………………………
…………………………………………………………………………………………
…………….……………………………………………………………………………
[3 marks]
(iii) Write the chemical formula for margarine in Figure 6.
[1 mark]
Name one example of a vegetable oil used in the production of margarine.
(c)
………..…………………………………………………………………………………
[1 mark]
3
SPM 2008/P2/Q4
The following information is about the compound C2H5OH.

Miscible in all proportions with water

Undergoes combustion

A member of a homologous series
(a)
What is the name of this compound?
(b)
……………………………………………………………………………………………………
[1 mark]
What is the general formula for the homologous series of this compound?
…………………………………………………………………………………………………..
[1 mark]
(c)
One mole of this compound undergoes complete combustion to form gas X and water
as shown below.
C2H5OH + mO2  nX + 3H2O
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Form 5 Chapter 2
(i)
State the name of gas X
(ii)
…………………………………………………………………………………………
[1 mark]
What are the values of m and n?
m = …………………………………………..
n = …………………………………………….
[2marks]
(d)
Compound C2H5OH reacts with ethanoic acid to produce compound Y which has a
sweet pleasant smell.
(i)
State the name of compound Y.
(ii)
……………………………………………………………………………………………
[1 mark]
Draw the structural formula of compound Y.
[1 mark]
(e)
Compound C2H5OH undergoes dehydration to produce ethene.
(i)
Suggest one dehydration agent for this reaction.
(ii)
…………………………………………………………………………………………...
[1 mark]
Draw an apparatus set-up for this dehydration reaction to collect ethane.
[2 marks]
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4
Form 5 Chapter 2
SPM 2008/P3/Q1
Diagram 1 shows three sets, Set I, Set II and Set III, of the apparatus set-up for an
experiment to investigate the effect of ethanoic acid and ammonia solution on the
coagulation of latex.
(a)
State one hypothesis based on Set I and Set II.
…………………………………………………………………………………………………
…………………………………………………………………………………………………..
[3 marks]
(b)
Record the time taken for the latex to coagulate in Set I and Set III.
Set I : …………………………………………………………………………………………..
Set III: …………………………………………………………………………………………..
[3 marks]
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Form 5 Chapter 2
(c) Construct a table to record the time taken for coagulation in Set I and Set III.
[3 marks]
(d)
State one observation that can be obtained from each set of this experiment.
Set I: ………………………………………………………………………………………….
Set II: ………………………………………………………………………………………….
(e)
Set III: ………………………………………………………………………………………….
[3 marks]
State the operational definition for the coagulation of latex.
…………………………………………………………………………………………………..
…………………………………………………………………………………………………..
(f)
(g)
……………………………………………………………………………………………………
[3 marks]
For this experiment, state:
(i)
The manipulated variable
(ii)
…………………………………………………………………………………………
The responding variable
(iii)
…………………………………………………………………………………………
The constant variable
(i)
………………………………………………………………………………………….
[3 marks]
Excess hydrochloric acid is added to the beaker in Set II after 2:00 p.m. What
observation can be made about the latex?
……………………………………………………………………………………………
…………………………………………………………………………………………….
(ii)
…………………………………………………………………………………………….
[3 marks]
Explain the answer in 1(g)(i)
……………………………………………………………………………………………..
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Form 5 Chapter 2
……………………………………………………………………………………………..
…………………………………………………………………………………………….
[3 marks]
(h)
Explain why latex can coagulate without acid in Set III.
………………………………………………………………………………………………….
…………………………………………………………………………………………………..
(i)
………………………………………………………………………………………………….
[3 marks]
(i)
[Concept: F5 Chapter 1: Rate of reaction]
Explain why the latex in Set I coagulates faster than the latex in Set III.
…………………………………………………………………………………………..
……………………………………………………………………………………………
(ii)
…………………………………………………………………………………………..
[3 marks]
The following is a list of chemical substances:
 Nitric acid
 Sodium hydroxide
 Methanoic acid
 Potassium hydroxide
Classify these substances into substances that can coagulate latex and
substances that cannot coagulate latex.
[3 marks]
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Form 5 Chapter 2
FORM 5 CHAPTERR 2 CARBON COMPOUNDS
Question 1 2003/P2/Q4
(a)
(b)
(c)
(d)
(e)
(f)
Heat supplied is uniform (or prevents the solution from evaporating too fast)
(i)
Esterification
(ii)
C2H5OH + CH3COOH  CH3COOC2H5 + H2O
(i)
Propyl ethanoate
(ii)
[Note: Choose any one of the following answers]
1. Fruity smell
2. Colourless liquid
3. Low boiling point (volatile) 4. Insoluble in water
(i)
C2H5OH  C2H4 + H2O
(ii)
C2H5OH + 2[O]  CH3COOH + H2O
Butane
Question 2 2004/P2/Q6
(a) (i)
Hydrogenation
(ii)
Vegetable oil changes from liquid to solid (or changes vegetable oil from unsaturated
fats to saturated fats or changes double bond in vegetable oil molecule to single
bond)
(b) (i)
Catalyst X : Nickel (or platinum)
Temperature : 100oC (or 200oC)
1. Presence of catalyst reduces the activation energy
(ii)
2. At a high temperature, particles possess high kinetic energy and
3. hence effective collision increases and rate of reaction increases
(iii)
or
(c)
Palm oil (or coconut oil or corn oil or other named oil example)
Question 3 2008/P2/Q4
(a) Ethanol
(b) CnH2n+1OH
(c) (i)
Carbon dioxide
(ii)
m=3 ,n=2
(d) (i)
Ethyl ethanoate
(ii)
(e)
(i)
[Choose any one of the following answers]
Porcelain chips or phosphoric acid or aluminium oxide
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Form 5 Chapter 2
(ii)
Question 4 2008/P3/Q1
(a) Acid coagulates latex while alkali does not coagulate latex.
(b) Set I: 5 minutes
Set II: 6 hours or 300 minutes
(c)
Set
Time taken / minute
(d)
(e)
(f)
(g)
(h)
(i)
I
5
III
300
Set I: A white solid lump is formed. (or latex coagulated)
Set II: There is no visible change observed. (or latex does not coagulate)
Set III: A white solid lump is formed. (or latex coagulated)
Operational definition for the coagulation of latex is latex becomes solid when acid is
added or when exposed to air.
(i)
The manipulated variable : Ethanoic acid and ammonia solution
(ii)
The responding variable : Latex coagulates or does not coagulate. (or time taken
for coagulation of latex)
(iii)
The constant variable
: Volume of latex, volume and concentration of acid and
ammonia solution. Temperature
Latex coagulates after excess hydrochloric acid is added. (or latex becomes solid
(i)
after excess hydrochloric acid is added.)
(ii)
[For more detailed pictorial explanation, please refer to text book page 93]
When acid is added, the H+ ions from the acid neutralized the ammonia in the
latex. The excess H+ ions then neutralized the negative charge on the protein
membrane. The protein membrane then breaks during collision and rubber
molecules combine and become entangled casing latex to coagulate.
[For more explanation, please refer to text book page 93]
This is because the bacteria from the air enter the latex. The growth and spread of
bacteria produce lactic acid that causes the coagulation of latex.
(i)
Latex in Set I coagulates faster than the latex in Set III because the concentration
of H+ ions is higher in Set I.
(ii)
Can coagulate latex
Nitric acid
Methanoic acid
Cannot coagulate latex
Potassium hydroxide
Sodium hydroxide
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Form 5 Chapter 2
FORM 5 CHAPTER 2 CARBON COMPOUNDS
ANALYSIS OF PAST YEAR QUESTIONS FROM 2003 - 2008
Year
2003
Paper No.
P2
Type of
question
S
Question No
4
1
2004
P3
E
S
P2
E
2005
P3
S
E
6
2
S
P2
E
S
2006
P3
E
S
P2
E
S
2007
P3
E
S
P2
E
S
3
2008
P3
E
9
S
P2
E
S
4
P3
E
S
1
2004/P2/Section B/Q2
Figure 2.1 shows changes of a carbon compound involving a series of reactions.
(a)
Draw the structural formulae of two propanol isomers.
Name both isomers.
(b)
[Concept: F4 Chapter 3 Chemical Formulae And Equations]
[4 marks]
The information below is regarding alkene Y:




Carbon 85.7%
Hydrogen 14.3%
Relative molecular mass = 42
Relative atomic mass of H = 1 and C = 12
Based on the information of the alkene Y:
(i)
Determine the molecular formula
(ii) Draw the structural formula
(iii) Name the alkene
(iv) Write the general formula for its homologous series.
[8 marks]
(c)
(i)
Table 2.2 shows the results of a test to differentiate between alkene Y and
propane.
Procedure
Observation
Bromine water is
added to alkene Y
Brown colour is
decolourized
Bromine water is
added to propane
Brown colour remains
Table 2.2
10
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Form 5 Chapter 2
Explain why there is difference in these observations
[4 marks]
(ii)
Table 2.3 shows results of latex coagulation.
Procedure
Observation
Propanoic acid is added to latex
Latex coagulates immediately
Latex is left under natural
conditions
Latex coagulates slowly
Table 2.3
Explain why there is a difference in these observations.
[4 marks]
2
SPM 2007/P2/Q9
(a) Diagram 9 shows how compound G is formed from an alkene.
Alkene + H2O
Phosphoric acid
300oC, 60 atm
Compound F
Porcelain chips
Heat
Compound G + H2O
(i)
Diagram 9
Name one alkene that has less than four carbon atoms. Draw its structural
formula
[2 marks]
(ii)
Based on the answer in 2(a)(i), what is the name of compound F and
Compound G?
[2 marks]
(iii)
State three chemical properties of compound F and three chemical
properties of compound G.
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Form 5 Chapter 2
[6 marks]
(b)
3
Alkene, alcohols and carboxylic acids are three different homologous series.
Construct a table to show the general formula, the functional group and the name
of a member in each of the series.
[10 marks]
SPM 2004/P3/Q3
The fruits in Figure 3.1 produce natural esters which have various tastes and scents.
FIGURE 3.1
Esters can be produced in the laboratory when an alcohol reacts with a carboxylic
acid.
Table 3.2 shows types of alcohol and carboxylic acid used to produce various esters.
These esters have a similar scent to the esters in fruits.
Alcohol
Ethanol
Methanol
Octanol
Pentanol
Carboxylic acid
Butanoic acid
Butanoic acid
Ethanopic acid
Ethanoic acid
Ester
Ethyl butanoate
Methyl butanoate
Octyl ethanoate
Pentyl ethanoate
Fruit
Pineapple
Apple
Orange
Banana
TABLE 3.2
You are required to prepare two different types of ester using the same carboxylic
acid with different alcohols. The two esters must be chosen from those shown in Table
3.2.
Use the information in Table 3.2 to plan a laboratory experiment to prepare the esters
and describe their scents.
Your explanation should include all the followings:
(a)
(b)
(c)
(d)
(e)
Aim of the experiment
Statement of hypothesis
List of substances and apparatus
Procedures of the experiment
Tabulation of data
[17 marks]
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1.
Form 5 Chapter 2
SPM 2006/P3/Q2
Diagram 2 shows the stretching phases of a vulcanized rubber and an unvulcanized
rubber strands.
Plan an experiment to compare one characteristic shown in Diagram 2 for both types
of rubber.
Your planning should include the following aspects:
(a) Aim of experiment
(b) All the variables
(c) Statement of the hypothesis
(d) List of substances and apparatus
(e) Procedure of the experiment
(f) Tabulation of data.
[17 marks]
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Form 5 Chapter 2
FORM 5 CHAPTER 2 CARBON COMPOUNDS
Question 1 2004/P2/Section B/Q2
(a)
Propan-1-ol
(b)
Propan-2-ol
(i)
85.7
No. of mol of carbon atom = 12 = 7.083
14.3
No. of mol of hydrogen atom = 1 = 14.1
No. of mol of carbon atom
No. of mol of hydrogen atom
1
 7.083
(integer)
14.3  2 (integer)
Empirical formula = CH2
Molecular formula of alkene Y : CnH2n
Given relative molecular mass = 42
Hence 12n + 2n = 42
14n = 42
n=3
 molecular formula of alkene Y is C3H6
(ii)
(c)
(iii)
(iv)
Propene
CnH2n
(i)
1. Alkene Y is an unsaturated hydrocarbon with a carbon-carbon double
bond.
2. When bromine water is added to alkene Y, brown colour is decolourised
because addition reaction (or bromination ) occurs.
3. Propane is a saturated hydrocarbon with carbon – carbon single bond.
4. No reaction occurs when bromine is added.
(ii)
1. Propanoic acid contains H+ ions
2. The H+ ions immediately neutralized the negative charge on the protein
membrane.
3. Hence when propanoic acid is added, latex coagulates immediately.
4. Bacteria from the air enter the latex.
5. The growth and spread of bacteria produce lactic acid slowly.
6. Hence when latex is left under natural conditions, it coagulates slowly.
Question 2 2007/P2/Q9
(a)
(i)
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Ethene
Form 5 Chapter 2
[ the other accepted answer is propene]
(ii)
Compound F is ethanol
Compound G is ethene
(iii)
Chemical properties of compound F (ethanol)
1. Ethanol burns completely in air (oxygen) to produce carbon dioxide and
water.
2. Ethanol react with acidified potassium dichromate(VI) to produce
ethanoic acid.
3. Ethanol undergoes dehydration to form ethene.
4. Ethanol react with carboxylic acid to produce ester.
[Choose any three.]
Chemical properties of compound G (ethene)
1. Ethene burns completely in air to produce carbon dioxide and water.
2. Ethene undergoes hydrogenation to produce ethane
3. Ethene reacts with water to form ethanol.
4. Ethene undergoes polymerization to form polyethane
[Choose any three. For other accepted answers please refer to text book page 46]
(b)
Homologous
series
Alkene
CnH2n
Alcohol
CnH2n+1OH
Carboxylic
acid
CnH2n+1COOH
General formula
Functional group
Carbon – carbon
double bonds
(or C = C)
Hydroxyl group
(or –OH )
Carboxyl group
(or COOH)
Member
Ethene
Ethanol
Ethanoic acid
Question 3 2004/P3/Q3
(a) Aim
To prepare two different types of ester using the same carboxylic acid with
different alcohols and describe their scents.
(b)
Hypothesis
Different alcohol produces different ester.
(c)
Substances
Methanol, ethanol, butanoic acid, concentrated sulphuric acid.
Apparatus
Measuring cylinder, test tubes, beakers, round bottom flask, Bunsen burner, dropper,
retort stand, test tube holder, condenser Liebig
(d)
Procedure
1. Using a measuring cylinder, 25 cm3 of methanol and 50 cm3 of butanoic acid is
separately measured and poured into a round bottom flask.
2. The mixture is then stirred.
3. Using a dropper, 10 drops of concentrated sulphuric acid is added and the
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Form 5 Chapter 2
apparatus is set up for reflux.
4. The mixture is then heated under reflux.
5. Ester is collected in a conical flask, smelled and its scent recorded.
6. Step 1 to step 5 is repeated by replacing methanol with ethanol while butanoic
acid is used in both experiments.
(e)
Tabulation of data
Alcohol
Carboxylic acid
Scent
Question 4 2006/P3/Q2
(a) Aim of experiment
To compare the elasticity of vulcanized and unvulcanized rubber.
(b)
All the variables
Manipulated variable: Vulcanized rubber and unvulcanized rubber
Responding variable: Change in length of rubber strip
Fixed variable
: Length (size) of rubber strip, mass of weight
(c)
Statement of the hypothesis
Vulcanized rubber is more elastic than vulcanized rubber.
(d)
Substances
Vulcanized rubber strip, unvulcanized rubber strip
Apparatus
Retort stand and clamps, Bulldog clips, metre rule, 50 g weight
(e)
Procedure
[Please refer to Practical chemistry book page 63 for complete diagram and
procedure.]
(f)
Tabulation of data
Length with weight
/cm
Initial length / cm
Vulcanized
rubber
Unvulcanized
rubber
16
Length after removal
of weight / cm