Students should learn Students should be able to a. Hydrocarbons from fossil fuels
coal, petroleum and natural gas as sources of fossil fuels and carbon compounds
composition of petroleum and its separation
gradation in properties of the various fractions of petroleum
heat change during combustion of hydrocarbons
major uses of distilled fractions of petroleum
consequences of using fossil fuels
describe the origin of fossil fuels
describe petroleum as a mixture of hydrocarbons and its industrial separation into useful fractions by fractional distillation
recognise the economic importance of petroleum as a source of aliphatic and aromatic
hydrocarbons (e.g. benzene)
relate the gradation in properties (e.g. colour, viscosity, volatility and burning characteristics) with the number of carbon atoms in the molecules of the various fractions
explain the demand for the various distilled fractions of petroleum
recognise combustion of hydrocarbons as an exothermic chemical reaction
recognise the pollution from the combustion of fossil fuels
evaluate the impact of using fossil fuels on our quality of life and the environment
suggest measures for reducing the emission of air pollutants from combustion of fossil fuels b. Homologous series, structural formulae
and naming of carbon compounds
unique nature of carbon
homologous series as illustrated by alkanes, alkenes, alkanols and alkanoic acids
structural formulae and systematic naming of alkanes, alkenes, alkanols and alkanoic acids
explain the large number and diversity of carbon compounds with reference to carbon’s unique combination power and ability to form different bonds
explain the meaning of a homologous series
understand that members of a homologous series show a gradation in physical properties and similarity in chemical properties
write structural formulae of alkanes
give systematic names of alkanes
extend the knowledge of naming carbon compounds and writing structural formulae to alkenes, alkanols and alkanoic acids
Students should learn Students should be able to c. Alkanes and alkenes
petroleum as a source of alkanes
alkanes
cracking and its industrial importance
alkenes
distinguish saturated and unsaturated hydrocarbons from the structural formulae
describe the following reactions of alkanes:
i. combustion
ii. substitution reactions with chlorine and bromine, as exemplified by the reaction of methane and chlorine (or bromine)
describe the steps involved in the
monosubstitution of methane with chlorine using suitable diagrams or equations
recognise that cracking is a means to obtain smaller molecules including alkanes and alkenes
describe how to carry out laboratory cracking of a petroleum fraction
explain the importance of cracking in the petroleum industry
describe the reactions of alkenes with the following reagents:
i. bromine
ii. potassium permanganate solution
demonstrate how to carry out chemical tests for unsaturated hydrocarbons
d. Addition polymers
monomers, polymers and repeating units
addition polymerisation
structures, properties and uses of addition polymers as illustrated by polyethene, polypropene, polyvinyl chloride, polystyrene and Perspex
recognise that synthetic polymers are built up from small molecules called monomers
recognise that alkenes, unsaturated compounds obtainable from cracking of petroleum fractions, can undergo addition reactions
understand that alkenes and unsaturated
compounds can undergo addition polymerisation
describe addition polymerisation using chemical equations
deduce the repeating unit of an addition polymer obtained from a given monomer
deduce the monomer from a given section of a formula of an addition polymer
Suggested Learning and Teaching Activities
Students are expected to develop the learning outcomes using a variety of learning experiences. Some related examples are:
searching for and presenting information about the locations of deposits of coal, petroleum and natural gases in China and other countries.
investigating colour, viscosity, volatility and burning characteristics of petroleum fractions.
searching for and presenting information about petroleum fractions regarding their major uses and the relation between their uses and properties.
discussing the relationship between global warming and the use of fossil fuels.
drawing structural formulae and writing systematic names for alkanes, alkenes, alkanols and alkanoic acids.
building molecular models of simple alkanes, alkenes, alkanols and alkanoic acids.
performing experiments to investigate the typical reactions of alkanes and alkenes.
studying the nature of the substitution reaction of methane and halogen with the aid of relevant video or computer animation.
performing an experiment on cracking of a petroleum fraction and testing the products.
searching for information and presenting arguments on the risks and benefits of using fossil fuels to the society and the environment.
discussing the pros and cons of using alternative sources of energy in Hong Kong.
searching for information or reading articles about the discovery of polyethene and the development of addition polymers.
investigating properties such as the strength and the ease of softening upon heating of different addition polymers.
writing chemical equations for the formation of addition polymers based on given information.
building physical or computer models of addition polymers.
performing an experiment to prepare an addition polymer, e.g. polystyrene, Perspex.
deducing the monomer from the structure of a given addition polymer.
Values and Attitudes
Students are expected to develop, in particular, the following values and attitudes:
to appreciate the importance of organising scientific information in a systematic way.
to recognise the benefits and impacts of the application of science and technology.
to value the need for the conservation of the Earth’s resources.
to appreciate the need for alternative sources of energy for sustainable development of our society.
to value the need for the safe use and storage of fuels.
to appreciate the versatility of synthetic materials and the limitations of their use.
to show concern for the environment and develop a sense of shared responsibility for sustainable development of our society.
STSE Connections
Students are encouraged to appreciate and comprehend issues which reflect the interconnections of science, technology, society and the environment. Related examples are:
The petroleum industry provides us with many useful products that have improved our standard of living. However, there are risks associated with the production, transportation, storage and usage of fossil fuels.
Emissions produced from the burning of fossil fuels are polluting the environment and are contributing to long-term and perhaps irreversible changes in the climate.
There are many examples of damages uncovered after using the applications of science and technology for a long period, e.g. the pollution problem arising from using leaded petrol and diesel; and the disposal problem for plastics. Therefore, it is essential to carefully assess the risks and benefits to society and the environment before actually using applications of science and technology in daily life.