Polystyrene

AUS-e-TUTE has just uploaded new resources for the Polystyrene topic.
AUS-e-TUTE members should log-in to view the new tutorial, play the polystyrene game and answer the polystyrene test questions.

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You can find out about membership at
http://www.ausetute.com.au/membership.html 

60 Second Chemistry Quiz Challenge

Over the past few years AUS-e-TUTE has received a lot of feedback.
One of the things that we hear a lot from teachers who are part of an AUS-e-TUTE Class or School Group Membership is that the students love to do the drills. They love to see how many questions they can get done quickly.
Well ..... we thought we could turn some basic chemistry concepts into timed challenges.
And ..... we've just uploaded the very first of these. We've called it the 60 Second Chemistry Quiz Challenge because you have just 60 seconds to answer as many questions correctly as you can.
This 60 Second Chemistry Quiz Challenge is called "It's Elementary", so I'm sure you can already guess what the questions are about :)

You can have a go yourself at:
http://www.ausetute.com.au/challenge.html

and let us know what you think by emailing us at

Ethanol Content of Beer and Wine

AUS-e-TUTE has added new resources for determining the content of ethanol in alcoholic beverages such as beer and wine.
Members should go to :
http://www.ausetute.com.au 
and log-in to the Members Only Test Centre to find the new Ethanol Redox Titration tutorial, game and test.
Teachers will find a new worksheet wizard for preparing Ethanol Redox Titration worksheets in the Teachers Only section of the website.

Polyesters

AUS-e-TUTE has just added new resources for the Polyester topic.
Members can log-in to read the new tutorial, play the new game, take the test or the exam.

http://www.ausetute.com.au

Polymer Banknotes

Australia was the first country to successfully replace paper notes with polymer notes, beginning with the circulation of $10 polymer banknotes back in 1988. Other countries, including Brunei, Canada, Fiji, Israel, Mauritius, New Zealand, Papua New Guinea, Romania, and Vietnam, have now abandoned paper in favour of polymer banknotes. Even the Bank of England will begin circulating polymer banknotes to replace the existing paper banknotes in 2016.

Australia is still the world's leading authority and prints polymer banknotes for more than 20 other countries in the world.

But what is a polymer banknote and why is it better than a paper banknote?

Find out in the March 2014 edition of AUS-e-NEWS, AUS-e-TUTE's free quarterly newsletter.

To subscribe to AUS-e-NEWS, email

and type subscribe as the subject of the email.

Graphene Capillary

Graphene is made up of carbon atoms, it is an allotrope of carbon.
 Each carbon atoms bonds to 3 other carbon atoms forming hexagons. Each hexagon shares each side with another hexagon. So this lattice of hexagons extends indefinitely, but it is only 1 carbon atom high! For this reason graphene is referred to as a two-dimensioal lattice or array.

Graphene is strong, light, nearly transparent and an excellent conductor of heat and electricity. Graphene is also hydrophobic, it repels water. However, narrow capillaries made out of graphene actually suck in water, if the water layer is only one atom thick.

Two years ago, researchers at the University of Manchester found that graphene capillaries could be made by stacking layers of graphene oxide on top of each to form a laminate. One-atom wide graphene capillaries are produced between these layers. These laminates are impermeable to all gases and vapours, except for water. This means that no gas or vapour, except for water, can pass through the laminate. Even helium, the smallest of the Nobel Gases cannot pass through the laminate.

These results suggest that graphene capillaries could be used to filter water. Researchers at the University of Manchester having been studying the use of graphene for water filtration and have found that ions less than 9 angstroms can quickly flow through with the water, but larger ions are blocked. With further research it is hoped to control the graphene mesh size to reduce it below 9 angstroms so that even the smallest ions like those found in seawater could be filtered out of water.

Reference:
R. K. Joshi, P. Carbone, F. C. Wang, V. G. Kravets, Y. Su, I. V. Grigorieva, H. A. Wu, A. K. Geim, R. R. Nair. Precise and Ultrafast Molecular Sieving Through Graphene Oxide Membranes. Science, February 14, 2014 DOI: 10.1126/science.1245711

Further Reading
Allotropes
Metric Conversions

Suggested Study Questions:

1. What is meant by the term "graphene is an allotrope of carbon?"
2. Name, and describe the structure of, two other allotropes of carbon.
3. Explain how the structure of graphene is different to the structure of graphite.
4. Why is graphene considered to be a good electrical conductor? 
5. Which other allotrope of carbon is considered to be good electrical conductor? Explain how this allotrope conducts electricity.
6. 1 angstrom = 1 Å = 10^-10 metres. Convert 9 Å to:
   • metres
   • millimetres
   • microns (micrometres)
   • nanometres
7. 1 picometre = 1 pm = 10^-12 metres. Convert 900 pm to :
   • metres
   • millimetres
   • microns (micrometres)
   • nanometres
   • angstroms
8. Consider the crystal ionic radius for each of the following ions commonly found in seawater:
   • Na⁺ : 116 pm
   • Mg²⁺: 86 pm
   • Cl^- : 167 pm
   • F^- : 119 pm
   • What is the diameter of each of these ions in angstroms?
   • Which, if any, of these ions would pass through a graphene capillary? Explain your answer.
9. A nitrate ion has a diameter of about 0.33nm and a sulfate ion has a diameter of about 0.49 nm. Which of these ions, if any, could pass through a graphene capillary? Explain your answer.

Turning Polyethylene Waste into Fuel

Low density polyethylene, LDPE, is used to make many things we use everyday such as plastic milk containers, cling wrap, and plastic bags. LDPE can be recycled quite easily, but a lot of LDPE ends up as rubbish in land fills.
Chemists in India have developed a commercially viable way to turn LDPE into a liquid fuel by heating the LDPE waste to between 400 and 500^oC over a kaolin catalyst which causes the long chain polymer chains to break apart. This process is known as thermo-catalytic degradation: thermo means heat, the catalyst is kaolin, and degradation means breaking apart. This thermo-catalytic degradation of LDPE produces much smaller carbon-based molecules. Gas Chromatography was used to characterise these smaller molecules, and it was found that they were mainly alkanes and alkenes between 10 and 16 carbon atoms long. This makes the mixture very similar to that found in petrochemical fuels. For example, the hydrocarbons in gasoline (petrol) typically have a chain length of between 4 and 12 carbon atoms while diesel fuel typically contains hydrocarbons with a chain length between 8 and 21 carbon atoms.

The catalyst, kaolin, is a layered, aluminosilicate clay mineral with the formula Al₂Si₂O₅(OH)₄. It acts as a catalyst by providing a large surface on which the polymer molecules can sit in an orientation favourable to the degradation under heat.

Using the kaolin catalyst at 450^oC, the thermo-catalytic degradation of 1 kg of LDPE produced 700 g of liquid fuel.

Reference:
Achyut Kumar Panda, Raghubansh Kumar Singh. Thermo-catalytic degradation of low density polyethylene to liquid fuel over kaolin catalyst. International Journal of Environment and Waste Management, 2014; 13 (1): 104 DOI: 10.1504/IJEWM.2014.058803

Further Reading:
Polythene (polyethylene): Properties, Production and Uses 
Gas Chromatography 
Alkanes: properties and uses
Alkenes: properties and uses
Ethene (ethylene): properties and uses
Silicates: structure and formula

Suggested Study Questions:

1. Give the molecular structure for ethene (ethylene).
2. Write an equation showing how ethene (ethylene) molecules can be polymerized to form polythene (polyethylene).
3. Name the type of polymerization reaction being described by the equation in question 2.
4. Explain, using a diagram of the partial structure of polythene (polyethylene), what happens when polyethylene undergoes thermo-catalytic degradation.
5. Describe the differences in the structures of alkanes and alkenes.
6. Draw a straight chain alkane with 10 carbon atoms.
7. Draw a structural isomer of the molecule in question 6.
8. Draw a straight chain alkene with 10 carbon atoms.
9. How many structural isomers of the molecule in question 8 do you think there would be? Support your answer with the structural formula for each of these structural isomers.
10. Why do you not find short carbon chain alkanes, between 1 and 4 carbon atoms long, in the liquid petrochemical fuels like gasoline (petrol) and diesel?