2016 Chemistry Calendar

The 2016 Chemistry Calendar is free to download.
This calendar has been designed to help students (and their teachers) keep track of important dates such as when assignments are due, tests/exams are scheduled, and any other special event.
And, it provides a handy reference for physical constants Chemistry students frequently use.
You can download your free 2016 Chemistry Calendar at:
http://ausetute.com.au/

Sulfuric Acid Train Derailed

A locomotive and all 26 carriages containing sulfuric acid derailed in north Queensland on Sunday 27^th December 2015.
The 800,000 L of sulfuric acid was bought by Incitec Pivot Limited (IPL) to be used in the production of ammonium phosphate fertiliser at its plant at Phosphate Hill (south of Mount Isa).

Glencore Plc has an agreement with Incitec Pivot Ltd to provide sulfur dioxide from the copper smelter to the Mount Isa acid plant. Sulfuric acid is produced by collecting and cleaning sulfur dioxide before converting it, first to sulfur trioxide, and then to sulfuric acid. The acid plant has the capacity to take up to 80% of the sulfur dioxide emissions from the copper smelter, significantly reducing the emissions of sulfur dioxide into the atmosphere. The sulfuric acid is then taken by train to Phosphate Hill, more than 100 km away.

Phosphate Hill combines a large open-cut phosphate mine with a plant for the production of fertiliser. The proved reserve is 29 Mt at 24.6% P₂O₅. The phosphate ore is first crushed and washed before being dissolved in sulfuric acid to produce phosphoric acid. Gypsum, CaSO₄.2H₂O, a by-product of the process, is stockpiled. The phosphoric acid is converted into ammonium phosphate fertiliser using ammonia gas:
 NH₃ + H₃PO₄ → NH₄H₂PO₄ (known as MAP)
2NH₃ + H₃PO₄ → (NH₄)₂HPO₄ (known as DAP)
The ammonium phosphate is then sent by train to the port at Townsville about 900 km away for shipment.

Wet weather hampered access to the disaster site for several days, but testing of the waters 8 km downstream in Horse Creek revealed changes in acidity. Locally sourced limestone is being used to treat the water.

References:
http://statements.qld.gov.au/Statement/2015/12/31/environmental-testing-continues-around-train-derailment-near-julia-creek
 http://www.abc.net.au/news/2015-12-30/fear-sulphuric-acid-leaked-train-derailed-waterway-julia-creek/7060070

Further Reading
 Copper Smelting
 Electrorefining
 Sulfuric Acid Production
Density Calculations
Percentage Composition 
 Intermolecular Forces
pH Scale 
pH Calculations for Acids  
Neutralisation

Suggested Study Questions:

1. Convert 800 000 L of sulfuric to a volume in:
   • megalitires (ML)
   • kilolitres (KL)
   • millilitres (mL)
2.  Assume the density of this sulfuric acid is 1.84 g mL^-1. What is the mass of 800,000 L of sulfuric acid?
3. Assuming all the sulfuric acid was distributed equally between the 26 carriages, what volume of sulfuric acid was contained in each carriage?
4. Write the chemical formula for each of the following:
• sulfur dioxide
• sulfur trioxide
• sulfuric acid
• sulfurous acid
5.  Convert 29 Mt of phosphate ore to a mass in
   • tonnes (t)
   • kilotonnes (kt)
   • kilograms (kg)
   • grams (g)
6.   A phosphate ore contains 24.6% P₂O₅
   • What mass of P₂O₅ is present in 1 tonne of the ore?
   • What mass of the element phosphorus is present?
   • What mass of the element oxygen is present?
7.  Give the systematic IUPAC name for each of the following:
   • NH₄H₂PO₄
   • (NH₄)₂HPO₄
8. Calculate the percentage by mass of nitrogen in
   • NH₄H₂PO₄
   • (NH₄)₂HPO₄
9. In situations in which too much nitrogen in the fertiliser can adversely affect germination, which phosphate, MAP or DAP, should be used? Explain your answer. 
10. Hygroscopy is the ability of a substance to  attract and hold water molcules from the surrounding environment. Which phosphate, MAP or DAP, would you expect to be more hygroscopic? Explain your answer.
11. Sulfuric acid from the derailed carriages is believed to be leaking into the water of Horse Creek. Do you expect the pH of the creek to be rising or falling? Explain your answer.
12. If the pH of the creek water was 3.0, calculate the concentration of hydrogen ions in the creek water.
13. Explain what the term neutralisation means.
14. Assuming limestone is composed of calcium carbonate only, write a balanced chemical equation for the reaction between sulfuric acid and limestone.
15. Would you describe the chemical reaction described by the equation in question 14 as a neutralisation reaction? Explain your answer.
16. In the laboratory you could use sodium hydroxide to neutralise sulfuric acid. Why isn't sodium hydroxide used to neutralise the sulfuric acid at the train derailment site?

 

Gifts for Chemists

What do you buy a chemist (professional, teacher, or student) as a gift?
They probably already have a cupboard full of mugs emblazoned with a Periodic Table right?
Ditto the tee-shirt.
Well the good people at Sigma-Aldrich (a company that supplies lab equipment) has a product range which it calls "nerdware", and I think you might find something appropriate there.
Go to http://www.sigmaaldrich.com and use the site's search for nerdware (or click the "Holiday Gifts for Scientists in Your Life" link)
I've already added the umbrella to my Christmas wishlist.

Sigma-Aldrich

Sigma-Aldrich

Sigma-Aldrich

Sigma-Aldrich

Sigma-Aldrich

Sigma-Aldrich

Cholera Vaccine

The holiday season is here, and some friends have decided to visit Panama (where else would an Engineer want to go for a holiday but to the Panama Canal?). One of the diseases they want protection against before traveling there is cholera which is caused by a water-born bacteria. The product they are taking is called DUKORAL® which comes in two parts. The first part part is a glass vial containing a whitish fluid which is the oral vaccine made up of inactivated cholera bacteria, which is probably of interest to the biology students reading this. Chemistry students, however, will be much more excited by the second part; a sachet containing a dry granular powder which is labelled as buffer.
The ingredients listed on the buffer sachet are:

• sodium bicarbonate
• citric acid, anhydrous
• raspberry flavour
• sodium carbonate, anhydrous
• sodium citrate
• saccharin sodium

The instructions for use by adults are:

1. Dissolve the effervescent granules from the buffer sachet in a glass of cool water (approximately 150 mL)
2.  Shake the vaccine vial
3. Add the vaccine to the effervescent (bubbly) solution. Mix well and drink mixture.

And, you have to take two of these doses 1 to 6 weeks apart, and 2 weeks before arrival at your destination.
The good news is that most people should be protected cholera for up to two years, so I guess my friends will make their way back to the tropics next year.

Suggested Reading
 http://www.ausetute.com.au/namiform.html
 http://www.ausetute.com.au/wriiform.html
http://www.ausetute.com.au/acidbase.html
 http://www.ausetute.com.au/buffers.html
http://www.ausetute.com.au/esters.html

Suggested Study Questions

1.  What is another, systematic name for sodium bicarbonate?
2. Give the molecular formula for each of the following:
   • sodium bicarbonate
   • citric acid, anhydrous
   • sodium carbonate, anhydrous
   • sodium citrate
3. Draw a structural formula for each of the following:
   • sodium bicarbonate
   • citric acid, anhydrous
   • sodium carbonate, anhydrous
   • sodium citrate
4. Use chemical terms to explain the relationship between:
   • sodium bicarbonate and sodium carbonate
   • citric acid and sodium citrate
5. Explain what a buffer is.
6. Explain why the dry, granular powder in the sachet was labelled "buffer".
7. Why do you think a buffer is needed for this vaccine to be effective?
8. What type of chemical compound is the "raspberry flavour" likely to be?
9. One molecule responsible for raspberry flavour is shown below:
   
   What 2 reactants would you need to produce to this molecule in the school laboratory?
10. What does the term effervescent mean?
11. Write a balanced chemical equation to show why effervescence is observed when the buffer in the sachet is added to water. 
12. What does the term "anhydrous" mean?
13. Why are some of the buffer sachet's ingredients listed as "anhydrous"?
14. What is the purpose of the saccharin in the buffer sachet?

Mine the Moon!

After The Jade Rabbit lander touched down on the Moon in December 2013, the Chinese space agency publicly suggested establishing mining bases on the Moon.

What could be so valuable that it would warrant the cost of going to the Moon to mine it then bringing it back to Earth to be used?

Gold? No.

Diamonds? No again.

Rare earth elements!

Why have rare earth elements (REE) become so important?

Find out in this edition of AUS-e-NEWS.

If you haven't received your December 2016 issue of AUS-e-NEWS in your inbox, please email us at  

 

The man who proved the moon isn’t cheese

Meet Emeritus Professor Ross Taylor AC, the Australian who analyzed the first moon rock samples in 1969, in Volume 46 Number 4 of the ANUreporter,

"With emission spectroscopy you can put a tiny amount of material into the flame and quickly identify any of 70 different elements from the spectral lines they produce. But those 70 elements could produce 100,000 possible lines," he says.
At 11.45am on 28 July, Taylor received the first samples. By 4pm, he delivered preliminary results to a press conference - significantly faster than the usual scientific process and with much more at stake.
The high-speed analysis had not been without hiccups. Taylor almost missed one of the most significant traits of the moon's chemistry, its significantly lower sodium levels than Earth.
The moon is also rich in chromium, which has a spectral line that almost perfectly disguised the low sodium result. Only moments before the press conference Taylor realised the mistake and corrected it.
"It would have ruined my reputation," he says.

Reference:
The man who proved the moon isn't cheese

Further Reading:
http://www.ausetute.com.au/emissions.html 
http://www.ausetute.com.au/flametest.html

Suggested Study Questions
1/ What is an emission spectrum?
2/ How can you produce the emission spectrum of metallic elements at school?
3/ How is the emission spectrum of an element used to confirm the existence of energy levels in atomic structure?
4/ What is a flame test?
5/ How does a flame test differ from emission spectroscopy?
6/ How is a flame test similar to emission spectroscopy?
7/ "With emission spectroscopy you can put a tiny amount of material into the flame and quickly identify any of 70 different elements from the spectral lines they produce." 
Explain how emission spectroscopy can be used to identify different elements.
8/ "But those 70 elements could produce 100,000 possible lines,"
Explain how such a huge number of lines can be produced from what seems like a much smaller number of elements.
9/ "The moon is also rich in chromium, which has a spectral line that almost perfectly disguised the low sodium result"
Explain how a chromium spectral line could disguise the low sodium result.
10/ Imagine you have helped Emeritus Professor Ross Taylor AC analyse these moon rock samples. Produce a scientific poster to communicate the results of this experiment to your class.

Cheesy Chemistry

Now here's the title of an article that sounds like it would make a great teaching and learning tool ..
"Food hacks: The science behind making perfect cheese melts and crispy cookies"
(Sydney Morning Herald, Monday 23rd November 2015)

"Science is great isn't it? ", writes the article's author.
Yes indeed, I couldn't agree more ... looks promising .....

"Even for those of us who find the periodic table of elements a foreign language, we can still reap the benefits of science's life-changing revelations."
Well, that's going a bit far (especially if you happen to teach/learn chemistry), but even so,  it still looks OK ......

"According to science, there's only one type of cheese for your toastie."
...mmm... possibly ...... "science" is rarely capable of making that kind of judgement ..... but we'll continue reading ....

until ........

" That cheese is the one with the right PH to balance the calcium, and release the casein (dairy protein) to create one big soft melty​ mess."
PH? Is that some kind of special food science thing? Could it be phosphorus monohydride?
No, it appears to simply be a mistake, which was, unfortunately repeated on the following line.
The author was referring to pH.

Nevertheless, did you know that different cheeses have different pH values?
I didn't!
So off I went to find the pH of some of my favourite cheeses:

cheese	pH
camembert	7.44
cheddar	5.90
cottage	4.75-5.02
cream	4.10-4.79
edem	5.40
gruyere	5.68-6.62
parmesan	5.20-5.30
stilton	5.70

Apparently, pH and temperature are both critical factors in the production of cheese:

• Addition of starter culture: temperature less than 20°C, pH = 5.1-5.3 (using rennet which contains enzymes for breaking down proteins)
•  Coagulation: temperature = 30°C, pH = 5.35 - 5.45
• Pressing: temperature 16-18°C (mild cheeses) or 25°C (hard cheeses), pH = 5.0-5.3
• Brining in salt solution: temperature 15°C, pH = 5.2
• Ripening: pH increases to optimum value as given in the table above.

A crumbly cheese, like a Cheshire cheese, has a low pH and low calcium content. At low pH the colloidal calcium phosphate between casein micelles becomes soluble and the size of these protein aggregates decreases, which, makes the cheese crumbly.

A low-acid cheese (high pH cheese) like Swiss cheese, has intact casein micelles which provide an extensive string of protein aggregates giving the cheese more elastic properties.

Further Reading:
http://www.ausetute.com.au/phscale.html
http://www.ausetute.com.au/phcalcs.html
http://www.ausetute.com.au/phhcalcs.html 
http://www.ausetute.com.au/enzymes.html 
http://www.ausetute.com.au/proteins.html
http://www.ausetute.com.au/aminoacid.html
http://www.ausetute.com.au/scientificm.html
http://www.ausetute.com.au/labreport.html


Suggested Study Questions:

1. What is meant by the term pH ?
2. Calculate the hydrogen ion concentration for each of the cheeses listed in the table above.
3. Arrange the cheeses in the table from lowest to highest pH.
4. Arrange the cheeses in the table from lowest hydrogen ion concentration to highest hydrogen ion concentration.
5. What is an enzyme?
6. What is a protein made up of?
7. Why do you think the temperature of the mixture during the addition of rennet and the coagulation stages is higher than at other stages during the production of cheese?
8. "According to science, there's only one type of cheese for your toastie."
    Do you think science can really tell you the best cheese to use for your toastie? Why or why not?
9. Who do you think the intended audience of this article is? Explain your answer.
10. Imagine you have just tested the pH the of various cheeses and that it is your results shown in the table above. Rewrite this article as if it were your lab report.