Uddingston Grammar School
Nat.6 Chemistry
Unit 2: Soaps, Fragrances and Skin Care
Homework
1. In which line of the table are fat, protein and soap correctly classified.
2. Soaps are produced from the following reaction
The reaction is an example of
A. Condensation
B. Esterification
C. Hydrolysis
D. Oxidation
3. Which of the following substances could be used as a soap?
A. Calcium Stearate
B. Stearic Acid
C. Potassium Stearate
D. Ethyl Stearate
4. Which of the following diagrams and explanations best describes a step in the
cleansing action of soap?
5. Which of the following could not be a possible source of a fatty acid?
A. Soaps
B. Edible oils
C. Emulsifiers
D. Essential oils
6. Which of the following could act as an emulsifier?
7. Myrcene is a simple terpene
Terpenes contain at least one isoprene unit.
Which of the following correctly highlights an isoprene unit?
8.
Limonene is one of the terpene molecules responsible for the flavour of lemons.
How many isoprene molecules are used in the production of one limonene
molecule.
A. 1
B. 2
C. 3
D. 4
9. An essential oil is
A. An oil which is essential in creating fragrance
B. A concentrated extract of the aroma compounds from plants
C. An unsaturated water soluble compound
D. A synthetic inorganic compound.
10. Humulene is a terpene which contributes to the aroma of beer.
How many isoprene units were used to form a humulene molecule?
A. 2
B. 3
C. 4
D. 5
11. Ibuprofen is available as an “infant formula” emulsion for young children.
The emulsifier used is polysorbate 80. Its structure is shown below.
a. Copy the part of the polysorbate 80 molecule that is hydrophobic.
(1)
b. Explain why this molecule acts as an emulsifier
(2)
c. The emulsion contains 2.0g of ibuprofen in every 100cm3of emulsion.
The recommended dose for treating a three month old baby is 0.050g.
Calculate the volume, in cm3, of “infant formula” needed to treat a three
month old baby.
(1)
12. To create a fragrance for men, the compound citetone is added.
a. Draw a structural formula for the alcohol that can be oxidised to form
civetone.
b. State if civetone shall undergo further oxidation
(1)
(1)
13. To make a shower gel produce a cold, tingling sensation when applied to the skin,
menthol is added.
Like terpenes, menthol is formed from isoprene.
a. Copy the menthol structure and circle an isoprene unit on your diagram
(1)
b. What group of compounds does isoprene belong to?
(1)
c. State the systematic name for isoprene.
(1)
14. The concentration of paracetamol in a solution can be determined by measuring
how much UV radiation it absorbs. The quantity of UV radiation absorbed is
directly proportional to the concentration of paracetamol.
The graph shows how the absorbance of a sample containing 0.040gl-1
paracetamol varies with wavelength.
The absorbance of a second sample of paracetamol solution measured at 245mm
was 0.90.
a. Determine the concentration, in gl-1, of this second paracetamol solution. (1)
b. A paracetamol molecule is shown below; state the name of one functional
group in the molecule below.
(1)
15. Traces of a liquid were discovered in a bottle believed to contain perfume
belonging to Queen Hatshepsut, ruler of Egypt over 3500 years ago.
Perfumes were made by dissolving plant extracts containing pleasant smelling
terpenes and esters in an edible oil. A little ethanol and water may also have
been used.
Using your knowledge of chemistry, comment on the possible smell(s) when
such a bottle is opened after being stored for thousands of years.
(3)
16. When forensic scientists analyse illegal drugs, anaesthetics such as lidocaine are
sometimes found to be present.
The gas chromatography below is from an illegal drug.
The structures of benzocaine and tetracaine are shown below.
a. Suggest why benzocaine has a shorter retention time than tetracaine. (1)
b. Why is it difficult to obtain accurate values for the amount of lidocaine
present in a sample containing large amounts of caffeine?
(1)
c. Roughly copy the chromatogram below and add a peak for a second sample
that only contains half the amount of tetracaine compared to the first.(1)
17. The structure of a soap molecule is represented below
This representation of a soap molecule illustrates that soaps have two parts to them;
1. An ionic head which is water soluble
2. A covalent hydrocarbon tail that is soluble in oil or grease
With the aid of a diagram and the above information, explain how soaps can clean
grease from clothing such as your school shirt.
30 Marks
(3)