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Form 4 Chapter 2 and 3
FORM 5 CHAPTER 5 CHEMICALS FOR CONSUMERS
ANALYSIS OF PAST YEAR QUESTIONS FROM 2003 – 2008
Year
Paper No.
Type of
question
Question No
1.
2003
P2
S
2004
P3
E
S
E
2
P2
S
E
2005
P3
S
E
2
P2
S
2
E
2006
P3
S
E
P2
S
2007
P3
E
S
E
1
P2
S
1
E
2008
P3
S
E
P2
S
P3
E
S
E
7
SPM 2004/P2/Q2
(a) In preparing soap, a strong alkali solution is added to fats. The mixture is heated
and then sodium chloride is added.
(i)
Name one strong alkali used in preparing soap.
………………………………………………………………………………………
[1 mark]
(ii)
Why is sodium chloride added to the mixture?
………………………………………………………………………………………
[1 mark]
(b)
The statement below is about soap and a detergent.
The cleaning action of a detergent is more
effective than a soap in hard water.
You have two socks stained with oil.
Describe briefly, the experimental procedure, observations and conclusions to
prove the above statement, by using substances such as soap, detergent and hard
water.
Procedure of the experiment:
……………………………………………………………………………………………
…………………………………………………………………………………………..
…………………………………………………………………………………………..
…………………………………………………………………………………………..
……………………………………………………………………………………………..
[3 marks]
Observations:
……………………………………………………………………………………………
…………………………………………………………………………………………..
[1 mark]
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Form 4 Chapter 2 and 3
Conclusions:
……………………………………………………………………………………………..
…………………………………………………………………………………………….
[1 mark]
(c)
Analgesic and psychotherapeutic medicines are used to treat patients. Aspirin is
an analgesic medicine and barbiturate is a psychotherapeutic medicine.
(i)
What is the function of a barbiturate?
……………………………………………………………………………………..
[1 mark]
(ii)
Children are advised not to take aspirin because it bleeding of the intestine
and stomach.
Suggest one after other medicine to replace the aspirin.
……………………………………………………………………………………..
[1 mark]
(iii)
Figure 2 shows the structural formula of aspirin.
Figure 2
What is the molecule formula of aspirin?
……………………………………………………………………………………..
[1 mark]
(iv)
What is the molecular mass of aspirin?
Use the information that the relative atomic mass of H = 1, C = 12 and O =
16.
………………………………………………………………………………………
[1 mark]
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2.
Form 4 Chapter 2 and 3
SPM 2005/P2/Q2
The following equation shows a reaction in the preparation of soap in a laboratory.
boil
Palm oil + concentrated sodium hydroxide
sodium palmitate (soap) + Glycerol
(a)
What is the name of this reaction?
………………………………………………………………………………………………
[1 mark]
[F5 Chapter 2 Carbon compounds]
(b)
(i)
What is the homologous series of palm oil?
………………………………………………………………………………………..
[1 mark]
(ii)
Complete the anion part of the soap particle in the space provided.
[1 mark]
[F4 Chapter 8 Salts]
(c)
A pupil want to prepare a potassium palmitate soap.
What alkali should he use?
……………………………………………………………………………………………
[1 mark]
(d)
Figure 2.1 shows part of the washing action of detergent particles on a grease
stained cloth.
Figure 2.1
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(i)
Form 4 Chapter 2 and 3
State the part of a detergent particle that is soluble in grease.
……………………………………………………………………………………….
[1 mark]
(ii)
Based on Figure 2.1 explain the washing action of detergent particles on
greasy stains.
……………………………………………………………………………………….
……………………………………………………………………………………….
……………………………………………………………………………………….
………………………………………………………………………………………
[3 marks]
(iii)
Complete Figure 2.2 to show the condition of grease and detergent particles
when the water is stirred.
Figure 2.2
[1 mark]
3.
SPM 2006/P2/Q1
(a) Diagram 1.1 shows a ginger plant.
Ginger can be used as a traditional medicine.
Diagram 1.1
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(i)
Form 4 Chapter 2 and 3
(ii)
Which of the parts P, Q, R or S, is used as the main source of medicine?
Mark (√) for your answer in the box provided in Diagram 1.1
[1mark]
What illness can be cured by using ginger?
(iii)
………………………………………………………………………………………..
[1 mark]
How is ginger used to treat the illness in 3(a)(ii)?
………………………………………………………………………………………..
[1 mark]
(b)
Table 1.1 shows the functions of three types of medicine.
Function
Type of medicine
Prevents pain
X: ………………………
Kills or prevents the reproduction of bacteria
Y: ………………………
Changes the emotions and behavior of the
patient
Z:
……………………….
(i)
(ii)
Table 1.1
Complete Table 1.1 to show which medicines have the functions given in the
table.
[3 marks]
What is the side effect of medicine of type X if it is used by a child of less
than 2 years old?
……………………………………………………………………………………….
[1 mark]
(iii)
A patient treated by medicine of type Y must complete all the supply given by
the doctor in order to make sure all the bacteria are killed.
What will happen if not all the bacteria are killed?
………………………………………………………………………………………..
[1 mark]
(iv)
Tranquilizer is an example of medicine of type Z.
Give one change that might happen to a patient’s emotions when treated
using this medicine.
……………………………………………………………………………………….
[1 mark]
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4.
Form 4 Chapter 2 and 3
SPM 2007/P2/Q1
The following equation shows how soap can be prepared.
Palm oil + sodium hydroxide
(a)
(i)
Substance X + Soap
What is the name of this process?
………………………………………………………………………………………
[1 mark]
(ii)
State the name of substance X.
………………………………………………………………………………………...
[1 mark]
(iii)
Sodium chloride solid is added to the soap mixture to complete this process.
Explain why.
………………………………………………………………………………………..
[1 mark]
(b)
Two cleaning agents, J and K, are used to wash clothes in sea water and river
water. Table 1 shows the result obtained.
Cleaning agent
(i)
Sea water
River water
J
Forms scum
Does not form scum
K
Does not form scum
Does not form scum
State the type of cleaning agents J and K.
J : ……………………………………………………………………………………
K: ……………………………………………………………………………………
[2 marks]
(ii)
What is the meaning of scum?
……………………………………………………………………………………….
[1 mark]
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(iii)
Form 4 Chapter 2 and 3
What are the two ions in sea water that cause the formation of scum?
1. …………………………………………………………………………………….
2. …………………………………………………………………………………….
[2 marks]
(iv)
State one advantage of cleaning agent J compared to K.
………………………………………………………………………………………..
[1 mark]
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Form 4 Chapter 2 and 3
CHAPTER 5 : CHEMICAL FOR CONSUMERS
1
SPM 2004/P2/Q2
a)
b)
i) Sodium hydroxide/potassium hydroxide
ii) To reduce the solubility of soap in water or to precipitate the soap formed.
Procedure of the experiment :
1. Two beakers are filled with hard water
2. Soap is added to one beaker and detergent is added to another beaker
3. The socks are dipped into each of the beakers and wash by scrubbing or
agitated
Observation :
Detergent in hard water
1. Socks is clean easily
2. No formation of scum
3. The water turns dirty
Soap in hard water
1. Socks still dirty
2. Scum forms
3. Water is less dirty
Conclusion :
Detergent cleans stains more effectively compared to soap in hard water. Detergent
can still performed its cleansing action and more effective than soap in hard water.
c)
2
i) To calm down patients so that they can sleep easily. As a sedative or to calm or
relax.
ii) Paracetamol
iii) C9H8O4
iv) Molecular mass
= (12 x 9) + (8 x 1)(4 x 16)
= 108 + 8 + 64
= 180
SPM 2005/P2/Q2
a) Saponification
b) i) Ester
ii) COOConcentrated potassium hydroxide solution
c)
d) i) Hydrophobic part or hydrocarbon part
ii) - Detergent ions reduce the surface tension of water
- Hydrophilic dissolves in water
- Hydrophobic dissolves in grease
- Mechanical agitation or scrubbing helps pull the grease free
(Refer to Chemistry Text Book Pg 185)
iii)
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3
SPM 2006/P2/Q1
a) i)
b)
4
Form 4 Chapter 2 and 3
ii) Stomach pain due to wind in stomach
iii) Extract the juice from the rhizome and drink
i) X : Analgesics
Y : Antibiotics
Z : Psychotherapeutic medicine
ii) Can cause bleeding in the stomach
iii) The bacteria becomes immune to medicine
iv) Get rid of anxiety
SPM 2007/P2/Q1
a) i) Saponification
ii) Glycerol
iii) To reduce the solubility of soap in water or to precipitate the soap
b) i) J : Soap
K : Detergent
ii) The insoluble precipitate formed when soap react with magnesium and calcium
ions (hard water)
iii) 1. Magnesium ion
2. Calcium ion
iv) J is biodegradable
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Form 4 Chapter 2 and 3
FORM 5 CHAPTER 5 CHEMICALS FOR CONSUMERS
ANALYSIS OF PAST YEAR QUESTIONS FROM 2003 – 2008
Year
Paper No.
Type of
question
Question No
2003
P2
S
2004
P3
E
2
S
E
P2
S
E
2005
P3
S
E
2
P2
S
2006
P3
E
S
2
E
P2
S
2007
P3
E
S
1
E
P2
S
1
E
2008
P3
S
E
P2
S
P3
E
S
E
7
1 SPM 2003/P2/Q2 (SECTION B)
(a) State two methods of food preservation which are used in our daily lives and
explain how the methods work.
[4 marks]
(b)
A student discovered that his socks have oily skin stains. He
washed them with soap.
Explain the cleansing action of soap on the oily stains.
(c)
[8 marks]
A student carried out four experiments to investigate the cleansing effects of soap
and detergent on oily soft water and hard water.
Table 2 shows the set-up of apparatus, types of water used, and the observations
for experiments I, II, III, and IV.
Observation
Table 2
Compare the cleansing effects between
(i)
Experiments I and II
(ii)
Experiments II and IV
Explain why there are differences in the observations. State the substance which
is more suitable as a cleansing agent to remove oily stains.
[8 marks]
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2
Form 4 Chapter 2 and 3
SPM 2008/P2/Q7
(a) Diagram 7.1 shows a list of ingredients for a type of food.
PINEAPPLE JELLY
AGAR-AGAR NANAS

Ethyl butanoate

Sucrose

Citric acid

Gelatin

Sodium benzoate
Diagram 7.1
From the list of ingredients, select two substances used as food additives.
State the function of each food additive that you have selected.
[4 marks]
(b)
Diagram 7.2 shows a conversation between Aida and May Ling.
I have a headache. The doctor
advised me to take this medicine
and follow his prescription
I have a bacterial infection. The
doctor advised me to follow his
prescription strictly.
Diagram 7.2
These two students met a doctor and some medicine were prescribed to them.
For each medicine, state its name, type and the correct usage.
[4 marks]
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(c)
Form 4 Chapter 2 and 3
Diagram 7.3 shows the apparatus used to investigate how to remove an oily stain
from a cloth and the observations made from that investigation.
Diagram 7.3
(i)
Based on the given information in Diagram 7.3, compare and explain the
effectiveness of the cleaning action between
 experiments I and III

(ii)
experiments II and IV
Identify the cleaning agents, A and B.
State which cleaning agent is more effective.
[10 marks]
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Form 4 Chapter 2 and 3
CHAPTER 5 : CHEMICAL FOR CONSUMERS
1
SPM 2003/P2/Q2 SECTION B
a)
Methods of food preservation
Adding salt or sugar
Adding vinegar or spices
Adding sodium nitrite or sodium nitrate,
benzoic acid or sodium benzoate, and
sulphur dioxide
Freezing or deep freezing
Drying or drain out water from food
Canned or sterilization or
pasteurisation or heating or vacuum
b)
Low temperature slows down the
growth of bacteria or microorganisms
Microorganisms cannot live without
water
Inhibit the growth of microorganisms
The cleansing action of soap: The socks are dipped in a soap solution
 Soap reduces the surface tension of water
 Soap increases the wetting ability of water on the surface of the socks
 The hydrophobic part of the soap dissolves in the oily stains
 The hydrophilic part is attracted to the water molecules




2
How the methods work
Draws the water out of the cells of
microorganisms
Retards the growth of microorganisms
Provides an acidic condition that
inhibits the growth of microorganisms
Slow down the growth of
microorganisms
Mechanical agitation during scrubbing helps pull the oily stains free and
break the oily stains into small droplets
The droplets do not coagulate and redeposit on the surface of the socks
due to the repulsion between the negative charges on the surface
The droplets are suspended in water forming an emulsion
Rinsing washes away these droplets and leaves the surface clean
SPM 2008/P2/Q7
a) 1. Ethyl butanoate is used as a flavouring agent
2. Sucrose is used as a flavouring agent
3. Citric acid is used as an antioxidant
4. Gelatin is used to thicken food
5. Sodium benzoate is used to slow down or prevent the growth of microorganism
b) The medicine prescribed to Aida is an analgesic. An analgesic is a medicine used
to relieve pain. Some of the common examples are aspirin, paracetamol and
codeine. Paracetamol is prescribed to Aida. It must be taken at the
recommended dose.
The medicine prescribe to May Ling is antibiotic. Antibiotics are used to kill or
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Form 4 Chapter 2 and 3
slow down the growth of bacteria. Some of the common examples of antibiotics are
penicillin and streptomycin. May Ling must take the full course of the antibiotic
prescribed.
c)
i) Experiment I and III
1. Both the cleaning agents A and B are effective in soft water. Soft water
does not contains calcium and magnesium ions.
2. Both are dissolves in soft water.
3. They are able to lower the surface tension of water. The water wets the
surface of the cloth thoroughly.
ii) Experiment II and IV
1. Cleaning agent A is not effective in hard water. Hard water contains
calcium and magnesium ions.
2. These ions react with the cleaning agent A to form an insoluble
precipitate (scum). Formation of scum greatly reduces the number of
cleaning agent A molecules available for cleaning.
3. Cleaning agent B is effective both in soft water and hard water. It can
perform its cleaning action in hard water.
4. Cleaning agent B does not form precipitate (scum) in hard water. Its
more effective in cleaning action than cleaning agent A.
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