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New 21st Century Chemistry

Suggested answers to in-text activities and unit-end exercises

Topic 8 Unit 29

I n-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.

Suggested answers to in-text activities and unit-end exercises 1 © Jing Kung. All rights reserved.Topic 8 Unit 29


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 livesThe following chart shows how medicines extend lives in the U.S.



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



Factors associated with longevityAccording 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

1747James Lind, a Scottish naval surgeon, discovered that citrus fruits could prevent scurvy (deficiency disorder resulting from a lack of vitamin C in the diet).

1796Edward 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.

1870sLouis 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.

1890Emil von Behring discovered antitoxins and used them to develop tetanus and diphtheria vaccines.

1896 First vaccine for typhoid fever.

1897Ronald 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.1890s Felix Hoffman developed aspirin.

1901Austrian-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.

1943Microbiologist Selman Waksman discovered the antibiotic streptomycin, later used in the treatment of tuberculosis and other diseases.

1945 First vaccine for influenza.

1953James 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.

1967South 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.

1977Sanger 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.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.htmlhttp://www.abpi.org.uk/publications/publication_details/azResearch/research-today1.asphttp://en.wikibooks.org/wiki/Introduction_to_Sociology/Demography

Checkpoint (page 6)a) 3-ethylpentaneb) 3,4-dimethylhexanec) 2,4-dimethylpent-2-ened) 3-methylhex-3-enee) 4-ethyl-2,5-dimethylheptane

Checkpoint (page 12)1 a) trichloromethane

b) 2-chlorohexanec) 2-chloro-1,1-difluoropropaned) 2,2-dibromo-3-chloropentane

2 a)

b)



c)

Checkpoint (page 16)1 a) methylpropan-1-ol

b) 4-methylpentan-2-olc) 2,3-dimethylbutan-1-old) 4-ethylcyclohexanole) hexane-2,3-diol

2 a)

b)

c)

d)

Checkpoint (page 19)1 a) methylpropanal

b) 4-methylpentan-2-onec) hexan-3-oned) 3-methylbenzaldehyde



2 a)

b)

c)

Checkpoint (page 20)1 a) pentanoic acid

b) 4-methylhexanoic acidc) ethanedioic acidd) 4-methylbenzoic acid

2 a)

b)

c)

Checkpoint (page 23)1 a) ethyl methanoate

b) methyl ethanoatec) ethyl benzoated) ethyl propanoate



2 a)

b)

c)

Checkpoint (page 25)1 a) butanamide

b) propan-1-aminec) 3-phenylpropan-1-amine

2 a)

b)

c)

Checkpoint (page 29)1 a) 3-oxobutanoic acid

b) 4-hydroxybutan-2-onec) 3-aminopropanoic acid



2 a)

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 boilingand 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.



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-solubleAlthough 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 compoundCommon name Origin of the common name

CH3COOH acetic acid from the Latin word for vinegar, acetum

HCOOH formic acidfrom the Latin word for ant, formica.(Ants can produce formic acid, which helps protect them from predators.)

benzoic acidderived from gum benzoin (the resinous product from styrax trees), which was for a long time the only source for benzoic acid.

HCHO formaldehyde the common name of an aldehyde is often derived from the name of the acid it forms.•formaldehyde derived from formic acid;•acetaldehyde derived from acetic acid.

CH3CHO acetaldehyde

CH3COCH3 acetone 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)

CH3CH(OH)CH3 isopropyl alcohol

common names for alcohols usually take the name of the corresponding alkyl group and add 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.

CHCl3 chloroform

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 offunctional group

ExampleName General formula

Alkenes CnH2n

Haloalkanes RX –X

Alcohols ROH –OH

Aldehydes RCHO



Ketones RCOR1

Carboxylic acids (H or R)COOH

Esters (H or R)COOR2

Amides RCONH2

Amines RNH2 –NH2

2 a) carbonyl groupb) carboxyl groupc) amide functional groupd) hydroxyl groupe) ester functional groupf) carbon-carbon double bond

3 a) NoThe first one is a carboxylic acid while the second one is an ester.

b) NoThe first one is a ketone while the second one is an aldehyde.

c) YesThey are both alcohols.

d) NoThe first one is an amide while the second one is an amine.



4Substituents 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:



c) Any one of the following:

d) Any one of the following:

e)

6 A7 D Option D — Both compounds are esters.8 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-.



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

carboxyl group.11 a) 4,5-dimethylhex-2-ene

b) 4-methylpentan-1-olc) 2-bromobutaned) 1,2-dimethylcyclohexanee) phenylethanalf) 2-methylpentan-3-oneg) hexanoic acidh) 3-hydroxybutanoic acidi) phenyl ethanoatej) 2-methylbutan-1-amine

12 a)

b)

c)

d)

e)



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.c) i)

ii) H–C–H bond angle: 109.5°C–C–O bond angle: 120°

iii) Permanent dipole-permanent dipole attractionsiv) ~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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