questions on fats and oils

1. 1
Carbon compounds
Module 3 –Fats and Natural Rubber
Name ………………………………………………….class…………………………teacher……………………………….
Answer the following questions
1) FATS
Oils and fats are esters
Carboxylic + Alcohol  Fats or + water
acids oil
Glycerol or 1,2,3-
Fatty acid
propanentriol
Has a very long chain carbon,
(about 10-20 atoms)
Examples, palmitic acids, stearic
acids, linoleic acids
I) From diagram above, what is the difference between a fat molecule and a fatty acid
molecule?
……………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………
a) Can hexanoic acid and pentanol react together to form Fat or Oil? Explain your answer
……………………………………………………………………………………………………………………………

2. 2
b) Can decanoic acid and glycerol react together to form Fat or Oil? Explain your answer
……………………………………………………………………………………………………………………………
c) State 2 similarities between fats and oils?
……………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………
d) Fill in the table below to list differences between oils and fats.
Oils Fats
a) sources
b) Physical state at room
temperature
c) Melting point
d) Fill in the table below to list differences between saturated and unsaturated fats
Unsaturated fats Saturated fats
a) Proportion of
molecules between
saturated and
unsaturated fats
b) Physical state at room
temperature
c) Melting point
d) sources
e) Why do unsaturated fats turn bad or spoil easily?

3. 3
……………………………………………………………………………………………………………………………………………
f) Explain how unsaturated fats can be changed to saturated fats?
…………………………………………………………………………………………………..
…………………………………………………………………………………………………..
…………………………………………………………………………………………………..
2) Natural rubber
a) List examples of natural polymers and their monomers
polymers monomers
1 Starch
2 Cellulose
3 Protein
4 Rubber
b) Draw the structural formula of natural rubber
………………………………………………………………………………………………………………………..
c) State the properties of natural rubber

4. 4
i) White ………………………………… at room temperature
ii) Elsticity that …………………………………………… overtime
iii) Soft
iv) Sensitive to …………………………………..
d) State 3 uses of natural rubber
i) …………………………………………………………………………………………………………………
ii) ………………………………………………………………………………………………………………..
iii) …………………………………………………………………………………………………………………..
COAGULATION OF LATEX -PROCESS
I) Latex is a …………………………………………………………
II) It consists of ………………………………………….particles dispersed in
…………………………………
III) Each rubber particle is made-up many long-chain
…………………………………………..molecules enclosed by a …………………………..-like
membrane which is ……………………………charged
Draw diagram
of one rubber particle

5. 5
DESCRIBE THE COAGULATION OF LATEX
i) The repulsion between the …………………………………………..charged particles
prevent the ………………………………..particles from coming close to each other.
Therefore latex could not …………………………………………
Draw diagram
ii) When an ………………………………………is added to latex, OR when latex is
exposed to ……………………………….., the …………………………..from the air enters
the latex and produce ………………………………………..acid that form
……………………ions. This ……………………………….ions neutralize the
…………………………………charges on the protein membrane.
Draw diagram

6. 6
iii) The rubber ………………………………………..can now come close together. This
enable them to ………………………………………….with one another resulting in
the ………………….. of the protein membranes.
Draw diagram
iv) The rubber molecules …………………………………… with one another and get
…………………………….. and thus causing latex to …………………………….
Draw diagram
IV) Describe how to prevent the coagulation of latex

7. 7
By adding …………………………………….solution, that contains ……………………………….ions
which ………………………………………. The acid produced by the bacteria . Therefore rubber
particles remain …………………………………… charged and the coagulation is ………………….
VULCANISED RUBBER
a) What is meant by vulcanization of rubber?
………………………………………………………………………………………………………………….
b) In industry, how does the vulcanization of rubber is carried out?
By heating latex with ……………………………………….. OR …………………………………………….
c) Describe how sulphur atoms change the properties of rubber
 In vulcanization , ………………….atoms form cross-………………between rubber …………………
 These cross ……………………………………….prevent rubber …………………………..from sliding too
much when …………………………………………..
 The rubber molecules return to their ………………………………….. position after being
stretched.
d) Draw cross-linkage of sulphur

8. 8
e) Compare and contrast the properties of vulcanized and unvulcanised rubber
 Similarities
Both are ………………………………………………………………
Both are …………………………………………………………….
 Differences
Vulcanised Differences Unvulcanised rubber
Elasticity
Hardness
Tensile strength
Resistance to heat
Effect of organic
solvents
a) State one advantage of natural rubber over synthetic rubber
Only natural rubber can take the tremendous ………………………, ……………………. and
………………………………produced during landing and taking off of an ……………………..
TQ TQTQTQ