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New 21st Century Chemistry
Suggested answers to in-text activities and unit-end exercises
Topic 8 Unit 29
In-text activities
Internet Search & Presentation (page 2)
Mortality
Some of the more common demographic measures of mortality include:
• crude death rate — the annual number of deaths per 1 000 people;
• infant mortality rate — the annual number of deaths of children less than 1 year old per
thousand live births;
• life expectancy — the number of years which an individual at a given age can expect to live at
present mortality rates.
Notice that the crude death rate can give a misleading impression. For example, the number of
deaths per 1 000 people can be higher for developed nations than in less developed countries,
despite the standards of health being better in developed countries. This is because developed
countries have relatively more older people. A more complete picture of mortality is given by a life
table which summarizes mortality separately at each age.
The following chart depicts infant mortality by region of the world. The less developed regions of
the world have higher infant mortality rates than the more developed regions.
The following chart depicts life expectancy by region of the world. Similar to infant mortality, life
expectancies are higher in more developed regions of the world.
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New 21st Century Chemistry
Life expectancy at birth in Hong Kong (1971 – 2009)
Source: http://www.chp.gov.hk/en/data/4/10/27/111.html
How medicines extend lives
The following chart shows how medicines extend lives in the U.S.
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Source: http://www.stv.columbia.edu/assets/STVLecture-Pfizer.pdf
Death rates by leading causes of death in Hong Kong, 2001 – 2009
(Number of deaths per 100 000 population)
Source: http://www.chp.gov.hk/en/data/4/10/27/117.html
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Factors associated with longevity
According to a recent research, one of the best predictors of longevity is education; the more
educated you are, the longer you can expect to live. The mechanism through which this works is not
the schooling itself, but the schooling's influence on other health-related behaviours. The more
education someone has, the lower is his / her likelihood of smoking and engaging in unhealthy and
high risk behaviours. Education also increases the probability of people engaging in healthy
behaviours, like frequently exercising.
Other factors associated with greater longevity include:
• wealth — money increases access to good healthcare, which improves health and increases
longevity;
• race — whites live longer than blacks, though this is due to other social disparities, like income
and education, and not to race itself;
• ability to delay gratification — with the ability to delay gratification, people live healthier lives
and engage in healthier behaviours (e.g. exercise);
• larger social networks — having a large group of friends and close relationships with relatives
increases the social support, which positively influences health;
• job satisfaction — people in more powerful and more satisfying jobs tend to be healthier than
people in less satisfying jobs.
Medical advances timeline
1747
James Lind, a Scottish naval surgeon, discovered that citrus fruits could prevent
scurvy (deficiency disorder resulting from a lack of vitamin C in the diet).
1796
Edward Jenner developed a method to protect people from smallpox by exposing
them to the cowpox virus. Vaccination with cowpox is made compulsory in Britain
in 1853. Jenner is sometimes called the founding father of immunology.
1800
Sir Humphry Davy announced the anesthetic properties of nitrous oxide.
1842
American surgeon Crawford Long used ether as a general anesthetic during surgery.
1870s
Louis Pasteur and Robert Koch establish the germ theory of disease. According to
the germ theory, a specific disease is caused by a specific organism. Before this
discovery, most doctors believed diseases were caused by spontaneous generation.
1879
First vaccine for cholera.
1881
First vaccine for anthrax.
1882
First vaccine for rabies.
1890
Emil von Behring discovered antitoxins and used them to develop tetanus and
diphtheria vaccines.
1896
First vaccine for typhoid fever.
1897
Ronald Ross, a British officer in the Indian Medical Service, demonstrated that
malaria parasites were transmitted via mosquitoes. The treatment for malaria was
identified much earlier (and is still used today).
1897
First vaccine for plague.
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1890s
1901
Felix Hoffman developed aspirin.
Austrian-American Karl Landsteiner described blood compatibility and rejection,
developing the ABO system of blood typing.
1921
Edward Mellanby discovers vitamin D and shows that its absence causes rickets.
1922
Insulin first used to treat diabetes.
1923
First vaccine for diphtheria.
1926
First vaccine for pertussis (whooping cough).
1927
First vaccine for tuberculosis.
1927
First vaccine for tetanus.
1928
Scottish bacteriologist Sir Alexander Fleming discovered penicillin.
1935
First vaccine for yellow fever.
1937
First vaccine for typhus.
1943
Microbiologist Selman Waksman discovered the antibiotic streptomycin, later used
in the treatment of tuberculosis and other diseases.
1945
First vaccine for influenza.
1953
James Watson and Francis Crick at Cambridge University described the structure of
the DNA molecule.
1954
Dr. Joseph Murray performed the first kidney transplant between identical twins.
1955
First oral treatment for diabetes introduced (Germany).
1962
First oral polio vaccine (as an alternative to the injected vaccine).
1964
First vaccine for measles.
1964
Ibuprofen (Boots) for arthritis and inflammation.
1967
First vaccine for mumps.
1967
South African heart surgeon Dr. Christiaan Barnard performed the first human heart
transplant.
1969
Salbutamol introduced for asthma.
1970
Levodopa (L-dopa) a major advance in Parkinson’s.
1970
First vaccine for rubella.
1974
First vaccine for chicken pox.
1977
Sanger and colleagues published first sequence of a whole DNA genome
(bacteriophage).
1977
First vaccine for pneumonia.
1978
First test tube baby was born in the U.K.
1978
First vaccine for meningitis.
1980
World Health Organization announced smallpox was eradicated.
1981
First vaccine for hepatitis B.
1983
HIV, the virus that causes AIDS, was identified.
1987
Zidovudine (Wellcome), first AIDS treatment, launched.
1992
First vaccine for hepatitis A.
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1996
Dolly the sheep became the first mammal cloned from an adult cell (died in 2003).
1996
Saquinavir (Roche) launched – first protease inhibitor for AIDS in the U.K.
1998
First vaccine for lyme disease.
2001
Sequencing of human genome reported to have been completed.
2001
Linezolid (Pharmacia) – first entirely new class of antibiotic in 30 years.
2007
Scientists discovered how to use human skin cells to create embryonic stem cells.
References:
http://www.infoplease.com/ipa/A0932661.html
http://www.abpi.org.uk/publications/publication_details/azResearch/research-today1.asp
http://en.wikibooks.org/wiki/Introduction_to_Sociology/Demography
Checkpoint (page 6)
a) 3-ethylpentane
b) 3,4-dimethylhexane
c) 2,4-dimethylpent-2-ene
d) 3-methylhex-3-ene
e) 4-ethyl-2,5-dimethylheptane
Checkpoint (page 12)
1 a) trichloromethane
b) 2-chlorohexane
c) 2-chloro-1,1-difluoropropane
d) 2,2-dibromo-3-chloropentane
2
a)
b)
c)
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New 21st Century Chemistry
Checkpoint (page 16)
1 a) methylpropan-1-ol
b)
c)
d)
e)
2
4-methylpentan-2-ol
2,3-dimethylbutan-1-ol
4-ethylcyclohexanol
hexane-2,3-diol
a)
b)
c)
d)
Checkpoint (page 19)
1 a) methylpropanal
b) 4-methylpentan-2-one
c) hexan-3-one
d) 3-methylbenzaldehyde
2
a)
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b)
c)
Checkpoint (page 20)
1 a) pentanoic acid
b) 4-methylhexanoic acid
c) ethanedioic acid
d) 4-methylbenzoic acid
2
a)
b)
c)
Checkpoint (page 23)
1 a) ethyl methanoate
b) methyl ethanoate
c) ethyl benzoate
d) ethyl propanoate
2
a)
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New 21st Century Chemistry
b)
c)
Checkpoint (page 25)
1 a) butanamide
b) propan-1-amine
c) 3-phenylpropan-1-amine
2
a)
b)
c)
Checkpoint (page 29)
1 a) 3-oxobutanoic acid
b) 4-hydroxybutan-2-one
c) 3-aminopropanoic acid
2
a)
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New 21st Century Chemistry
b)
c)
d)
Discussion (page 40)
1 a) The boiling point of a compound depends on the strength of its intermolecular attractions.
The intermolecular attractions in alkanes are van der Waals’ forces.
The number of electrons in one alkane molecule increases as the number of carbon atoms in
the molecule increases.
Hence the strength of van der Waals’ forces between alkane molecules also increases.
More heat is needed to separate the molecules during boiling
and thus the boiling points of the alkanes increase with the number of carbon atoms in the
molecules.
b) Van der Waals’ forces exist in alkane while both hydrogen bonds and van der Waals’s
forces exist in alcohols.
Hydrogen bonds are stronger than van der Waals’ forces.
Hence more heat is needed to separate the alcohol molecules during boiling.
c) An alcohol molecule is made up of two parts — the non-polar hydrocarbon part and the
polar –OH group.
As the number of carbon atoms in an alcohol molecule increases, the influence of the –OH
group becomes less significant compared with that of the increasingly large hydrocarbon
part. Properties of the higher alcohols tend more and more towards those of the
corresponding alkanes.
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New 21st Century Chemistry
2
a) Amine molecules can form hydrogen bonds with water molecules.
Due to these strong attractions between amine molecules and water molecules, amines with
small alkyl groups are soluble in water.
b) The water solubility of amines decreases as the number of carbon atoms in their molecules
increases.
c) Oil-soluble
Although the compound has a polar –NH2 group, the larger organic part (benzene ring and
the ester group) renders it water-soluble but oil-soluble.
Library Search & Presentation (page 42)
Structural formula
of compound
CH3COOH
HCOOH
HCHO
CH3CHO
CH3COCH3
Common name
Origin of the common name
acetic acid
from the Latin word for vinegar, acetum
formic acid
from the Latin word for ant, formica.
(Ants can produce formic acid, which helps
protect them from predators.)
benzoic acid
derived from gum benzoin (the resinous
product from styrax trees), which was for a
long time the only source for benzoic acid.
formaldehyde
the common name of an aldehyde is often
acetaldehyde
derived from the name of the acid it forms.
•formaldehyde derived from formic acid;
•acetaldehyde derived from acetic acid.
acetone
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common names for ketones can be derived by
naming the two alkyl or aryl groups bonded to
the carbonyl group as separate words followed
by the word ketone.
•acetophenone (i.e. phenylethanone)
•diethyl ketone (i.e. pentan-3-one)
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New 21st Century Chemistry
common names for alcohols usually take the
name of the corresponding alkyl group and add
CH3CH(OH)CH3
CHCl3
isopropyl alcohol
chloroform
the word ‘alcohol’, e.g. methyl alcohol and
ethyl alcohol. Propyl alcohol may be n-propyl
alcohol or isopropyl alcohol, depending on
whether the hydroxyl group is bonded to the 1st
or 2nd carbon of the propane chain.
chloroform was named and chemically
characterized in 1834 by the French chemist
Jean-Baptiste Dumas [Fr. chloroforme, from
chlor- ‘chlorine’ + formique ‘formic (acid)’].
Unit-end exercises (pages 46 – 52)
Answers for the HKCEE (Paper 1) and HKALE questions are not provided.
Homologous series
Formula of
functional group
Name
General formula
Alkenes
CnH2n
Haloalkanes
RX
–X
Alcohols
ROH
–OH
Aldehydes
RCHO
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Example
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New 21st Century Chemistry
2
3
Ketones
RCOR1
Carboxylic acids
(H or R)COOH
Esters
(H or R)COOR2
Amides
RCONH2
Amines
RNH2
–NH2
a)
b)
c)
d)
e)
f)
a)
carbonyl group
carboxyl group
amide functional group
hydroxyl group
ester functional group
carbon-carbon double bond
No
The first one is a carboxylic acid while the second one is an ester.
b) No
The first one is a ketone while the second one is an aldehyde.
c) Yes
They are both alcohols.
d) No
The first one is an amide while the second one is an amine.
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4
Substituents
Name (prefix)
–Cl
chloro
–Br
bromo
–I
iodo
–CH2CH3
ethyl
–CH2CH2CH3
propyl
–CH(CH3)2
isopropyl
phenyl
5
a) Any one of the following:
b) Some possible structures are shown below:
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New 21st Century Chemistry
c) Any one of the following:
d) Any one of the following:
e)
6
7
8
A
D Option D — Both compounds are esters.
B
9
C A compound containing both a C=C group and a
group is regarded as a ketone.
The IUPAC name of the compound is hex-4-en-2-one. The double bond takes the suffix
form -en-.
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10 B (2) Vanillin contains a –OH group. Thus it is able to form hydrogen bonding.
(3) Vanillin does NOT belong to the carboxylic acid series because it does NOT contain a
11 a)
b)
c)
d)
e)
f)
g)
h)
carboxyl group.
4,5-dimethylhex-2-ene
4-methylpentan-1-ol
2-bromobutane
1,2-dimethylcyclohexane
phenylethanal
2-methylpentan-3-one
hexanoic acid
3-hydroxybutanoic acid
i) phenyl ethanoate
j) 2-methylbutan-1-amine
12 a)
b)
c)
d)
e)
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f)
g)
h)
i)
j)
13 Alcohols that are low in the homologous series (methanol, ethanol and propan-1-ol) are miscible
with water in all proportions.
An alcohol molecule is made up of two parts — the non-polar hydrocarbon part and the
polar –OH group.
The water solubility of an alcohol is due to the hydrogen bonding formed between the –OH
group of the alcohol molecule and water molecules.
As the number of carbon atoms in an alcohol molecule increases, the influence of the –OH
group becomes less significant compared with that of the increasingly large hydrocarbon part.
Properties of the higher alcohols tend more and more towards those of the corresponding
alkanes.
Hence the water solubility of alcohols decreases as the number of carbon atoms in their
molecules increases.
14 —
15 a) Van der Waals’ forces
b) The boiling point of a compound depends on the strength of its intermolecular attractions.
Hydrogen bonds exist in propan-1-ol while only van der Waals’ forces exist in butane.
Hydrogen bonds are stronger than van der Waals’ forces.
Hence more heat is needed to separate the propan-1-ol molecules during boiling.
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c) i)
ii) H–C–H bond angle: 109.5°
C–C–O bond angle: 120°
iii) Permanent dipole-permanent dipole attractions
iv) ~55 °C
d) Propanone molecules can form hydrogen bonds with water molecules, but butane molecules
cannot.
16 The boiling point of a compound depends on the strength of its intermolecular attractions.
Relatively weak instantaneous dipole-induced dipole attractions exist in alkanes.
The carbonyl group in an aldehyde is polar. Permanent dipole-permanent dipole attractions exist
in aldehydes.
Hence the boiling points of aldehydes are higher than those of alkanes of similar relative
molecular masses.
Hydrogen bonds exist in alcohols and carboxylic acids.
Hence their boiling points are higher than those of aldehydes of similar relative molecular
masses.
The boiling points of carboxylic acids are higher than those of alcohols as the molecules of
carboxylic acids can form more extensive hydrogen bonds.
The van der Waals’ forces between molecules increase as the length of the carbon chain in the
molecules increases. Hence the boiling points of the members in a homologous series usually
increase with relative molecular mass.
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