Taylor High School
Higher Chemistry
1. Which of the following is an ester?
Unit 2 Section 7
4. The structural formula for glycerol
is
2. Fats and oils can be classified as
5. Which consumer product is least
likely to contain esters?
A
B
C
D
A
B
C
D
soaps
fatty acids
esters
polyesters
6. Fats have a higher melting points
than oils because comparing fats to oils
3. The conversion of linoleic acid,
C18H32O2, into stearic, C18H36O2, is
likely to be achieved by
A
B
C
D
Flavourings
Perfumes
Solvents
Toothpaste
A fats have more hydrogen bonds
B fats have more cross-links between
molecules
C fat molecules are more loosely
packed
D fat molecules are more saturated
hydrogenation
hydrolysis
hydration
dehydration
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Taylor High School
Higher Chemistry
7. An ester has the structural formula:
Unit 2 Section 7
9. In the formation of “hardened” fats
from vegetable oils, the hydrogen
On hydrolysis, the ester would produce
A causes cross-linking between chains
B causes hydrolysis to occur
C increases the carbon chain length
D reduces the number of carbon to
carbon double bonds
A
B
C
D
10. Olestra is a calorie free fat made by
reacting fatty acids with sucrose. The
structure of a sucrose molecule can be
represented as shown.
ethanoic acid and propan-1-ol
ethanoic acid and propan-2-ol
propanoic acid and propan-1-ol
propanoic acid and propan-2-ol
8. An ester is prepared from methanoic
acid and ethanol. Which of the following
is the full structural formula for the
ester produced.
How many fatty acid molecules can react
with one molecule of sucrose?
A
B
C
D
3
5
8
11
11. The compound CH3CH2COO-Na+ is
formed by reaction between sodium
hydroxide and
A
B
C
D
2
propanoic acid
propan-1-ol
propene
propanal
Taylor High School
Higher Chemistry
12. Aspirin is one of the most widely
used pain relievers in the world. It has
the structure:
15. Fats are formed by the condensation
reaction between glycerol molecules
and fatty acid molecules. In this
reaction the mole ratio of glycerol
molecules to fatty acid molecules is:
A
B
C
D
Which two functional groups are
present in an aspirin molecule?
A
B
C
D
Aldehyde and ketone
Carboxyl and ester
Ester and aldehyde
Hydroxyl and carboxyl
CH3CH2CH2COOCH2CH3
The name of the ester is:
propyl propanoate
ethyl butanoate
butyl ethanoate
ethyl propanoate
14. Which of the following compound
would react with sodium hydroxide
solution to form a salt?
A
B
C
D
1:1
1:2
1:3
3:1
16. Which of the following reactions
takes place during the “hardening” of
vegetable oil?
A
B
C
13. An ester has the following structural D
formula:
A
B
C
D
Unit 2 Section 7
CH3CHO
CH3COOH
CH3COCH3
CH3CH2OH
3
Addition
Hydrolysis
Dehydration
Oxidation
Taylor High School
Higher Chemistry
Unit 2 Section 7
17. The following triglyceride is found in some fats and oils.
(a) The hydrolysis of the triglyceride produces an alcohol and long chain fatty
acids. Name the alcohol produced by the hydrolysis of the triglyceride>
1
(b) What happens to triglyceride molecules in the conversion of oils to hardened
fats?
1
18. Esters are important compounds which have many applications.
(a) Some of the instructions outlining the laboratory preparation of an ester are
shown below.
1. Mix 1 cm3 of the alkanol with 1 cm3 of the alkanoic acid in a test tube.
2.
3.
4. After 20 mins, pour the contents of the test tube into a beaker containing
sodium hydrogen carbonate solution.
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Taylor High School
Higher Chemistry
Unit 2 Section 7
Add appropriate instructions for steps 2 and 3.
2
(b) The full structural formula for an ester is shown below.
Give the systematic name of the alkanol used in making this ester.
1
(c) State a use of esters.
1
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Taylor High School
Higher Chemistry
Unit 2 Section 7
19. Two reaction of propanoic acid are shown.
(a) Draw the full structural formula for ester X.
1
(b) Give a name for compound Y, which reacts with propanoic acid to form sodium
propanoate.
1
20. Perfumes normally contain three groups of components called top note, the
middle note and the end note.
(a) The top note components of a perfume form vapours easily. Two compounds
found in top note components are:
(i) With reference to the structure of these compounds, why are they likely to
have pleasant smells?
1
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Taylor High School
Higher Chemistry
Unit 2 Section 7
(ii) Describe a chemical test which would distinguish between these two
compounds and give the result of the test.
1
(b) The middle note compounds form vapours less readily than the top note
compounds. A typical compound of the middle note is:
Due to the hydrogen bonding 2-phenylethanol forms a vapour less readily than p
-cresyl acetate. In the box above, draw another molecule of 2-phenylethanol and
use a dotted line to show where a hydrogen bond exists between the two
molecules.
1
(c) The end note of a perfume has a long lasting odour which stays with the user.
An example of an end note compound is:
Draw the structure of the alcohol which would be formed by the reduction of
civetone.
1
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Taylor High School
Higher Chemistry
Unit 2 Section 7
21. Biodiesel is a mixture of esters which can be made by heating rapeseed oil with
methanol in the presence of a catalyst.
(a) Name compound X.
1
(b) A typical diesel molecule obtained from crude oil has the molecular formula
C16H34 (hexadecane).
Other than the ester group, name a functional group present in biodiesel
molecules which is not present in hexadecane.
1
(c) Vegetable oils like rapeseed oil are converted into fats for use in the food
industry. What name is given to this process?
1
22. The structure of a molecule found in olive oil can be represented as shown.
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Taylor High School
Higher Chemistry
22. continued
(a) Olive oil can be hardened using a nickel catalyst to produce a fat.
(i) What type of catalyst is nickel in this reaction?
Unit 2 Section 7
1
(ii) In what way does the structure of a fat molecule differ from that of an oil
molecule?
1
(b) Olive oil can be hydrolysed using sodium hydroxide solution to produce sodium
salts of fatty acids.
(i) Name the other product of this reaction.
1
(ii) Give a commercial use for the sodium salts of fatty acids.
1
23. The structure of a fat molecule is shown below.
(a) When the fat is hydrolysed, a fatty acid is obtained. Name the other product
in this reaction.
1
(b) Oils are liquid at room temperature; fats are solid. Why do oils have lower
melting points than fats?
1
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Taylor High School
Higher Chemistry
Unit 2 Section 7
24. An ester can be prepared by the following sequence of reactions.
(a) (i) Draw a structural formula for compound A.
1
(ii) But-2-ene and compound A undergo the same type of reaction in step 2.
Name this type of reaction.
1
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Taylor High School
Higher Chemistry
Unit 2 Section 7
(iii)Acidified potassium dichromate solution can be used to carry out Step 3.
What colour change would be observed?
(iv) Name compound B.
1
1
(b) (i) What evidence would show that an ester had been formed in Step 4?
1
(ii) Give one use for esters.
1
25. Ethyl pentanoate is an ester. It can be prepared in the lab as shown below.
(a) (i) Why is a water bath used for heating?
1
(ii) What is the purpose of the wet paper towel?
1
(b) Draw a structural formula for ethyl pentanoate.
1
(c) on next page.
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Taylor High School
Higher Chemistry
Unit 2 Section 7
(c) Starting with a mass of 3.6 g of ethanol, and a slight excess of pentanoic acid,
a student achieved a 70% yield of ethyl pentanoate (mass of 1 mole = 130g).
Calculate the mass of ester obtained. Show your working clearly.
2
26. (a) Ethanol and propanoic acid can react to form an ester.
(i) Draw the structural formula for this ester.
1
(ii) Draw a labelled diagram of the assembled apparatus that could be used to
prepare this ester in the lab.
1
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Taylor High School
Higher Chemistry
Unit 2 Section 7
26. continued
(iii) Due to hydrogen bonding, ethanol and propanoic acid are soluble in water
whereas the ester produced is insoluble. In each of the boxes below, draw a
molecule of water and use a dotted line to show where a hydrogen bond could
exist between the organic molecule and the water molecule.
1
(b) Pyrolysis (thermal decomposition) of esters can produce two compounds, an
alkene and an alkanoic acid, according to the following equation.
(R and R’ represent alkyl groups)
Draw a structural formula for the ester that would produce 2-methylbut-1-ene
and methanoic acid on pyrolysis.
1
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Taylor High School
Higher Chemistry
Unit 2 Section 7
27. (a) Acidified potassium dichromate solution can be used to oxidise some
alcohols to aldehydes and then to carboxylic acids, eg
ethanol
ethanal
ethanoic acid
(i) Name the type of alcohol that can be oxidised to an aldehyde.
(ii) What colour change would be observed when acidified potassium
dichromate solution is used to produce ethanoic acid from ethanal?
1
1
(b) Ethanol (GFM = 46 g) and ethanoic acid (GFM = 60 g) react to form the ester
ethyl ethanoate (GFM = 88 g).
ethanol
+
ethanoic acid
ethyl ethanoate +
water
(i) Describe how the reaction mixture would be heated in the lab formation of
the ester.
1
(ii) Use the above information to calculate the percentage yield of ethyl
ethanoate if 5.0 g of ethanol produced 5.8 g of ethyl ethanoate on reaction with
excess ethanoic acid.
Show your working clearly.
2
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Taylor High School
Higher Chemistry
Unit 2 Section 7
28. Glycerol trinitrate is an explosive with the structure shown.
(a) Glycerol trinitrate is produced from glycerol.
(i) Draw the structural formula for glycerol.
1
(ii) Name the group of naturally occurring esters that can be hydrolysed to obtain glycerol.
1
(b) When exploded, glycerol trinitrate decomposes to give nitrogen, water, carbon
dioxide and oxygen.
Balance the equation for this reaction.
C3H5N3O9(l)
N2(g) + H2O(g) + CO2(g)
15
+
O2(g)
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Taylor High School
Higher Chemistry
Unit 2 Section 7
29. When a mixture of solid sodium hydroxide and solid sodium ethanoate is
heated, methane gas and solid sodium carbonate are produced.
NaOH (s)
+
CH3COONa (s)
CH4 (g) +
Na2CO3 (s)
(a) Draw a diagram of an apparatus which could be used for this reaction showing
how the methane gas can be collected and its volume measured.
2
(b) Name the gas produced when sodium propanoate is heated with solid sodium
hydroxide.
1
30. One of the chemicals released in a bee sting is an ester that has the
structure shown.
This ester can be produced by the reaction of an alcohol with an alkanoic acid.
(a) Name this acid.
1
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Taylor High School
Higher Chemistry
Unit 2 Section 7
30. continued
(b) The ester can be prepared in the lab by heating a mixture of the reactants
with a catalyst.
(i) Name the catalyst used in the reaction.
1
(ii) What improvement could be made to the experiment set-up shown in the
diagram?
1
(c) If there is a yield of 65%, calculate the mass of ester produced, in grams,
when 4.0 g of the alcohol reacts with a slight excess of the acid.
GFM of alcohol = 88g
GFM of ester = 130g.
Show your working clearly.
2
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Taylor High School
Higher Chemistry
Unit 2 Section 7
31. A typical triglyceride found in olive oil is shown below.
(a) To which family of organic compounds do triglycerides belong?
1
(b) Olive oil can be hardened for use in margarines. What happens to the
triglyceride molecules during the hardening of olive oil?
(c) Give one reason why oils can be a useful part of a balanced diet.
1
32. Alkanols can be oxidised to alkanoic acids
(a) (i) Why can step 1 be described as an oxidation reaction?
1
(ii) Acidified potassium dichromate solution can be used to oxidise propanal in
step 2. What colour change would be observed?
1
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Taylor High School
Higher Chemistry
Unit 2 Section 7
32. continued
(b) Propan-1-ol and propanoic acid react to form an ester. The mixture of excess
reactants and product is poured onto sodium hydrogencarbonate solution.
(i) What evidence would show that an ester is formed?
1
(ii) Draw the structure of this ester.
1
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