chem hsc summary Essay examples

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Pages: 16

CHEMISTRY DOT POINT SUMMARY
TOPIC NAME
1. Fossil Fuels provide both energy and raw materials such as ethylene, for production of other substances.
STUDENTS LEARN ABOUT:
a) Construct word and balanced formulae equations of chemical reactions as they are encountered

b) Identify the industrial source of ethylene from the cracking of some of the fractions from the refining of petroleum.

Cracking is the name given to the chemical process of breaking large hydrocarbon molecules into smaller ones. For example breaking dodecane, C12H26 into octane: C8H18 and butane: C4H8. There are two types of cracking; catalytic cracking and thermal cracking.

c) identify that ethylene, because of the high reactivity of its double bond, is readily transformed into many useful products.

A substitution reaction is a reaction in which an atom in a molecule is replaced by another atom or group of atoms.

d) identify that ethylene serves as a monomer from which polymers are made.

e) Identify polyethylene as an addition polymer and explain the meaning of this term.

Polymer
Name and structure of the monomer
Common uses
Polyethylene
Ethylene (ethene)
CH2 = CH2
LDPE: milk bottles, soft toys, cling wrap
HDPE: kitchen utensils, more ridged toys, rubbish bins
Poly (vinyl chloride), PVC
Vinyl chloride (chloroethene)
CH2=CH-Cl
Electrical insulations, garden hoses, drainage and sewerage pipes, downpipes
Polystyrene
Styrene (phenylethene)
Insert diagram

Car battery cases, tool handles, modern furniture, CD cases, foam packing material, disposable drink cups (foam and clear)

f) outline the steps in the production of polyethylene as an example of a commercially and industrially important polymer.

g) Identify the following as commercially significant monomers:
- vinyl chloride
- styrene
By both their systematic and common names

h) describe the uses of the polymers made from the above monomers in terms of their properties

STUDENTS LEARN TO:
i) Gather and present information from first-hand or secondary sources to write equations to represent all chemical reactions encountered in the HSC course.

j) Identify data, plan and perform a first-hand investigation to compare the reactivities of appropriate alkenes with the corresponding alkanes in bromine water
Aim- To compare the reactivities of alkanes and alkenes
Hypothesis- The alkene will be more reactive due to the double bond
Equipment- Cyclohexene, cyclohexane, bromine water, 2 test tubes, test tube rack
Method-
1. Have 1mL of the hexane and hexane in separate test tubes
2. Add 10 drops of bromine water and shake
3. Record results
Results-
Properties
Cyclohexane
Cyclohexene
Odour
Strong
Glue smell
Colour before Br water
Clear
Clear
Colour of Br water
Orange
Orange
Colour after shaking
Deep orange
Clear

Conclusion-
As the cyclohexene resulted in a clear substance it shows that it is more reactive. This is due to the double bond in the alkene.
The cyclohexane gradually reacted to become more clear as it reacts with light.

k) analyse information from secondary sources such as computer simulations, molecular model kits or multimedia resources to model the polymerisation process.
- MOLYMODS

TOPIC NAME
2. Some scientists research the extraction of materials from biomass to reduce our dependence on fossil fuels.
STUDENTS LEARN ABOUT:
a) discuss the need for alternative sources of the compounds presently obtained from the petrochemical industry
Petrochemicals are chemicals made from compounds in petroleum or natural gas. Currently Australia has petroleum reserves that will last about ten years and natural gas reserves that will last about one hundred years. Fossil fuels have taken hundreds of millions of years to accumulate. Over 95% of fossil fuel is burnt as a source of energy and once burnt, fossil fuels are no longer available. Less than 5% of fossil fuel is used to make plastics and…