The quintessential Chemistry Calendar for 2014 is now available.
You can download your free calendar at
http://www.ausetute.com.au/downloads.html
Happy New Year !
Monday, December 30, 2013
Thursday, December 26, 2013
Extrapolation and Interpolation
AUS-e-TUTE has just added a new tutorial, game and test to help you learn how to make predictions using graphs.
Using our new resources, you will have no trouble explaining and using the terms interpolation and extrapolation!
Using our new resources, you will have no trouble explaining and using the terms interpolation and extrapolation!
Tuesday, December 17, 2013
Writing Lab Reports
AUS-e-TUTE has just added new resources to help you write lab reports.
You will find new tutorials, games and tests for each of the following:
1. Writing Lab Reports (an overview)
2. Accuracy and Precision
3. Experimental Errors (random vs systematic)
4. Variables (dependent vs independent)
5. Potting points on a graph
Just log-in in the Members Only Test Centre to see all these new resources.
Teachers will also find a new resource, wizard that generates a pre-test for stoichiometry.
The results of the pre-test will help teachers identify the students that need help with simple algebra, or with reading and interpreting algebraic questions, before you plow on into stoichiometry.
Just log-in in the Teachers area to see all this new resource.
You will find new tutorials, games and tests for each of the following:
1. Writing Lab Reports (an overview)
2. Accuracy and Precision
3. Experimental Errors (random vs systematic)
4. Variables (dependent vs independent)
5. Potting points on a graph
Just log-in in the Members Only Test Centre to see all these new resources.
Teachers will also find a new resource, wizard that generates a pre-test for stoichiometry.
The results of the pre-test will help teachers identify the students that need help with simple algebra, or with reading and interpreting algebraic questions, before you plow on into stoichiometry.
Just log-in in the Teachers area to see all this new resource.
Thursday, December 12, 2013
Argon Hydride in Space
Almost 1,000 years ago, the Chinese recorded a bright new object in the night sky. This is believed to be a star that exploded. The remnant of that exploded star is now called the Crab Nebula and it is about 6,500 light years from Earth.
Europe launched its Herschel Space Observatory in 2009, and in 2012 Astronomers used it to study the emission lines from Crab Nebula. What the scientists found were 2 bright emission lines from an area of shining dust. It was only by consulting databases of the known properties of different molecules that the scientists could finally identify these emission lines as coming from a very special molecule, argon hydride.
Argon hydride is special because it is the first time that molecules of a Noble Gas (Group 18) element have been found in space. On Earth, the naturally occurring Noble Gas (Group 18) elements are monatomic gases. Atoms of Noble Gas elements have a full valence shell of electrons so they tend not to react with other atoms.
Something really interesting must be happening in the Crab Nebula for argon hydride to be formed naturally. The researchers believe that the argon formed when the original star exploded. The intense energy of the explosion stripped electrons off the argon atoms, ionising them. Ionised argon atoms then reacted with hydrogen molecules to form argon hydride molecules.
Reference
M. J. Barlow, B. M. Swinyard, P. J. Owen, J. Cernicharo, H. L. Gomez, R. J. Ivison, O. Krause, T. L. Lim, M. Matsuura, S. Miller, G. Olofsson, E. T. Polehampton. Detection of a Noble Gas Molecular Ion, 36ArH , in the Crab Nebula. Science, 2013; 342 (6164): 1343 DOI: 10.1126/science.1243582
Further Reading
http://ausetute.com.au/trendec.html
http://ausetute.com.au/trendie.html
http://ausetute.com.au/massconv.html
http://ausetute.com.au/members/emissions.html
Suggested Study Questions:
Europe launched its Herschel Space Observatory in 2009, and in 2012 Astronomers used it to study the emission lines from Crab Nebula. What the scientists found were 2 bright emission lines from an area of shining dust. It was only by consulting databases of the known properties of different molecules that the scientists could finally identify these emission lines as coming from a very special molecule, argon hydride.
Argon hydride is special because it is the first time that molecules of a Noble Gas (Group 18) element have been found in space. On Earth, the naturally occurring Noble Gas (Group 18) elements are monatomic gases. Atoms of Noble Gas elements have a full valence shell of electrons so they tend not to react with other atoms.
Something really interesting must be happening in the Crab Nebula for argon hydride to be formed naturally. The researchers believe that the argon formed when the original star exploded. The intense energy of the explosion stripped electrons off the argon atoms, ionising them. Ionised argon atoms then reacted with hydrogen molecules to form argon hydride molecules.
Reference
M. J. Barlow, B. M. Swinyard, P. J. Owen, J. Cernicharo, H. L. Gomez, R. J. Ivison, O. Krause, T. L. Lim, M. Matsuura, S. Miller, G. Olofsson, E. T. Polehampton. Detection of a Noble Gas Molecular Ion, 36ArH , in the Crab Nebula. Science, 2013; 342 (6164): 1343 DOI: 10.1126/science.1243582
Further Reading
http://ausetute.com.au/trendec.html
http://ausetute.com.au/trendie.html
http://ausetute.com.au/massconv.html
http://ausetute.com.au/members/emissions.html
Suggested Study Questions:
- 1 light year is approximately 9.5 x 1015 metres. How far from Earth is the Crab Nebula in kilometres?
- 1 astronomic unit (1 AU) is approximately 1.5 x 1011 metres. What is the distance between Earth and the Crab Nebula in astronomic units?
- What sort of instrument can be used to observe the emission lines of hot gases?
- Explain how these emission lines are produced.
- Give the electron configuration of an atom of argon.
- With reference to the electron configuration of argon, explain why compounds of argon are not found naturally on Earth.
- Write an equation to show the loss of an electron from a gaseous argon atom.
- Explain how the hydride ion can be formed from a hydrogen atom.
- Give a likely molecular formula for a molecule of argon hydride.
- Is argon hydride most likely to an ionic compound or a covalent compound? Explain your answer.
Monday, December 9, 2013
Excel : Line of Best Fit
You can easily use Microsoft Excel to find the equation for the line of best fit for experimental data points.
Remember that the equation of a straight line is y = mx + b
where m is the slope (gradient) of the line and b is the intercept on the y axis (that is, when x =0).
Microsoft excel will calculate both the slope of the line, m, and the y-intercept, b, for you.
First you will need to open up a new excel spreadsheet and set up your data.
Here we have used Row 1 of columns A and B for our headings (x values and y values).
Various values for x and y have then been entered into the cells:
Next, we highlight any two adjacent cells (empty cells) somewhere else in the same spreadsheet, for example A8 and B8
Next to the fx symbol above the cell headings A, B, etc, type in =LINEST(B2:B6, A2:A6)
then press Ctrl+Shift+Enter simultaneously.
(B2 is the first y value to be used in the calculation and B6 is the last y value to be used in the calculation. Similarly, A2 is the first of the x values to be used in the calculation and A6 is the last of the x values to be used in the calculation.)
Your spreadsheet should now look this:
The number in cell A8 is the slope (m) of the line of best fit.
The number in cell B8 is the y-intercept (b) of the line of best fit, that is, the point with coordinates (0,b)
The equation for the line of best fit for this data is y = 10.50606x -0.21918
In order to draw the line of best fit for the experimental data above, we only need to calculate new values for y using the equation for the line of best fit (that is, the first and last points on the line of best fit).:
given x=1.02 ,then, y = (10.50606 x 1.02) -0.21918 = 10.5
and x=4.86 , then, y =(10.50606 x 4.86) -0.21918 = 50.8
Plot the points (1.02, 10.5) and (4.86, 50.8) on the graph of experimental data and draw a straight line between these two points. This is the line of best fit for the experimental data in the table.
Further Activities:
Go to http://www.ausetute.com.au/members/bestfitline.html
1/ Enter the data above into the tool for calculating the two points needed to draw a line of best fit. Check the new y values above, and see what the graph looks like.
Graph the data points in questions 2 to 5 below and draw the line of best fit:
2/ (0.23, 9.75), (0.94, 6.39), (1.77, 5.73), (4.59, 4.91), (11.52, 0.33)
3/
4/
5/ At time 0, the temperature of a reaction mixture was 25oC. The temperature of the reaction mixture was then recorded every minute for 4 minutes. The results of the experiment were temperatures of 29oC, 32oC, 35oC and 40 oC.
Remember that the equation of a straight line is y = mx + b
where m is the slope (gradient) of the line and b is the intercept on the y axis (that is, when x =0).
Microsoft excel will calculate both the slope of the line, m, and the y-intercept, b, for you.
First you will need to open up a new excel spreadsheet and set up your data.
Here we have used Row 1 of columns A and B for our headings (x values and y values).
Various values for x and y have then been entered into the cells:
| cell | A | B |
| 1 | x values | y values |
|---|---|---|
| 2 | 1.02 | 11.0 |
| 3 | 2.05 | 21.3 |
| 4 | 2.96 | 31.2 |
| 5 | 4.12 | 39.7 |
| 6 | 4.86 | 53.4 |
Next, we highlight any two adjacent cells (empty cells) somewhere else in the same spreadsheet, for example A8 and B8
| cell | A | B |
| 1 | x values | y values |
|---|---|---|
| 2 | 1.02 | 11.0 |
| 3 | 2.05 | 21.3 |
| 4 | 2.96 | 31.2 |
| 5 | 4.12 | 39.7 |
| 6 | 4.86 | 53.4 |
| 7 | ||
| 8 | ||
Next to the fx symbol above the cell headings A, B, etc, type in =LINEST(B2:B6, A2:A6)
then press Ctrl+Shift+Enter simultaneously.
(B2 is the first y value to be used in the calculation and B6 is the last y value to be used in the calculation. Similarly, A2 is the first of the x values to be used in the calculation and A6 is the last of the x values to be used in the calculation.)
Your spreadsheet should now look this:
| cell | A | B |
| 1 | x values | y values |
|---|---|---|
| 2 | 1.02 | 11.0 |
| 3 | 2.05 | 21.3 |
| 4 | 2.96 | 31.2 |
| 5 | 4.12 | 39.7 |
| 6 | 4.86 | 53.4 |
| 7 | ||
| 8 | 10.50606 | -0.21918 |
The number in cell A8 is the slope (m) of the line of best fit.
The number in cell B8 is the y-intercept (b) of the line of best fit, that is, the point with coordinates (0,b)
The equation for the line of best fit for this data is y = 10.50606x -0.21918
In order to draw the line of best fit for the experimental data above, we only need to calculate new values for y using the equation for the line of best fit (that is, the first and last points on the line of best fit).:
given x=1.02 ,then, y = (10.50606 x 1.02) -0.21918 = 10.5
and x=4.86 , then, y =(10.50606 x 4.86) -0.21918 = 50.8
| cell | A | B | C |
| 1 | x values | y values | new y values |
|---|---|---|---|
| 2 | 1.02 | 11.0 | 10.5 |
| 3 | 2.05 | 21.3 | |
| 4 | 2.96 | 31.2 | |
| 5 | 4.12 | 39.7 | |
| 6 | 4.86 | 53.4 | 50.8 |
| 7 | |||
| 8 | 10.50606 | -0.21918 |
Plot the points (1.02, 10.5) and (4.86, 50.8) on the graph of experimental data and draw a straight line between these two points. This is the line of best fit for the experimental data in the table.
Further Activities:
Go to http://www.ausetute.com.au/members/bestfitline.html
1/ Enter the data above into the tool for calculating the two points needed to draw a line of best fit. Check the new y values above, and see what the graph looks like.
Graph the data points in questions 2 to 5 below and draw the line of best fit:
2/ (0.23, 9.75), (0.94, 6.39), (1.77, 5.73), (4.59, 4.91), (11.52, 0.33)
3/
| time / min | mass / g |
|---|---|
| 0 | 102.8 |
| 2 | 73.4 |
| 4 | 48.7 |
| 6 | 27.3 |
| 8 | 10.9 |
4/
| volume / mL | 5.0 | 10.0 | 15.0 | 20.0 | 25.0 |
| mass / g | 3.2 | 7.1 | 9.4 | 13.5 | 14.8 |
5/ At time 0, the temperature of a reaction mixture was 25oC. The temperature of the reaction mixture was then recorded every minute for 4 minutes. The results of the experiment were temperatures of 29oC, 32oC, 35oC and 40 oC.
Wednesday, December 4, 2013
CGS and the Solvay Process
Coal seam gas (CSG) is any naturally occurring gas, such as methane, that is trapped in underground coal seams by water and pressure. Methane, often called natural gas, is a commercially valuable resource, so mining companies drill into the coal seam, pump the water out, which releases the pressure and forces the gases to the surface. Queensland is believed to have about 98% of Australia's coal seam gas reserve. More than 4,000 CSG wells in Queensland account for about 17% of that state's electricity. NSW has about 500 CSG wells.
The water that is produced in coal seam gas mining is not suitable for human consumption. The water is most often very salty and can contain heavy metals and toxic compounds.
A new drilling project in the Pilliga Forest in the north-west of NSW is expected to produce an average of 3 tonnes of salt a day over three years!
That's a lot of salt! Left to itself, lying around near the mine, it will poison land and waterways. So what can you do with all this salt?
Salt, sodium chloride, is an important commercial chemical. It is used to produce chlorine and sodium hydroxide, and is used in other industrial process, it is used directly for snow and ice control, as a mineral in animal diets, as a preservative, as a flavouring agent, and as a reagent for water softening. The total (deliberate) production of sodium chloride world-wide is about 250 million tonnes per year.
One way to get rid of the salt produced in coal seam gas mining is to turn it into something else, sodium carbonate for instance.
In Australia, the Penrice Soda Products company in Osborne, South Australia, operates a plant using the Solvay Process to turn sodium chloride into sodium carbonate.
The overall chemical equation for the Solvay Process is
CaCO3(s) + 2NaCl (aq)
Na2CO3(aq) +
CaCl2(aq)
CaCO3(s) is present in limestone and the NaCl is the by-product of the CGS mining.
The company currently produces about 325,000 tonnes of sodium carbonate every year.
Further Reading:
density
yield
Solvay Process
Suggested Study Questions:
The water that is produced in coal seam gas mining is not suitable for human consumption. The water is most often very salty and can contain heavy metals and toxic compounds.
A new drilling project in the Pilliga Forest in the north-west of NSW is expected to produce an average of 3 tonnes of salt a day over three years!
That's a lot of salt! Left to itself, lying around near the mine, it will poison land and waterways. So what can you do with all this salt?
Salt, sodium chloride, is an important commercial chemical. It is used to produce chlorine and sodium hydroxide, and is used in other industrial process, it is used directly for snow and ice control, as a mineral in animal diets, as a preservative, as a flavouring agent, and as a reagent for water softening. The total (deliberate) production of sodium chloride world-wide is about 250 million tonnes per year.
One way to get rid of the salt produced in coal seam gas mining is to turn it into something else, sodium carbonate for instance.
In Australia, the Penrice Soda Products company in Osborne, South Australia, operates a plant using the Solvay Process to turn sodium chloride into sodium carbonate.
The overall chemical equation for the Solvay Process is
CaCO3(s) + 2NaCl (aq)
Na2CO3(aq) +
CaCl2(aq)CaCO3(s) is present in limestone and the NaCl is the by-product of the CGS mining.
The company currently produces about 325,000 tonnes of sodium carbonate every year.
Further Reading:
density
yield
Solvay Process
Suggested Study Questions:
- How much NaCl will the Pilliga Forest mining project produce in one year?
- Assume that there are 4,500 CSG mines in Australia and they each produce 3 tonnes of salt a day. How much salt will be produced in one year in Australia from CSG mines?
- The density of sodium chloride is about 2.2 g/cm3. Calculate the volume of salt produced each day by the Pilliga Forest CSG mine.
- Assume a single truck can carry 100 tonnes of salt. How many truck loads of salt will be produced at the Pilliga Forest CSG mine each year?
- Give one environmental issue that would be raised in trucking salt over large distances. Explain how the problem could be reduced.
- Give one commercial problem associated with trucking salt over large distance using the same truck. Explain how the problem could be reduced.
- What is the maximum amount, in tonnes, of sodium carbonate that could be produced using 1 truck load of sodium chloride?
- What is the maximum amount, in tonnes, of calcium carbonate required to completely convert 1 tonne of sodium chloride to sodium carbonate?
- If the actual yield of sodium carbonate is 86.2%, what mass of sodium carbonate would be produced from the complete reaction of 1 tonne of sodium chloride?
- Assuming the solvay process was used to convert all the salt from all Australia's CSG mines into sodium carbonate, how much sodium carbonate would be be produced?
- World production of sodium carbonate is currently about 42 million tonnes per year. If Australia began production of sodium carbonate using all the salt produced in the CSG mines, what percentage increase would there be in world production of sodium carbonate?
- What would you suggest Australia do with the salt produced as a by-product of coal seam gas mining?
Tuesday, December 3, 2013
Ice Calorimeter
Scientists began studying the heat produced in chemical reactions long before they even understood what a chemical reaction was!
At a time when scientists still believed that matter was made up of elements like Aristotle's earth, air, fire and water, and the concept of energy had not yet been formulated, they were using the newly invented
mercury-in-glass thermometer to measure the temperature of substances and the results were surprising.
The December 2013 edition of AUS-e-NEWS discusses the development of the very first calorimeter, the ice calorimeter, in 1780.
AUS-e-NEWS is AUS-e-TUTE's FREE quarterly newsletter.
If you would like to subscribe to AUS-e-NEWS, please email
and type subscribe as the subject of the email.
At a time when scientists still believed that matter was made up of elements like Aristotle's earth, air, fire and water, and the concept of energy had not yet been formulated, they were using the newly invented
mercury-in-glass thermometer to measure the temperature of substances and the results were surprising.
The December 2013 edition of AUS-e-NEWS discusses the development of the very first calorimeter, the ice calorimeter, in 1780.
AUS-e-NEWS is AUS-e-TUTE's FREE quarterly newsletter.
If you would like to subscribe to AUS-e-NEWS, please email
and type subscribe as the subject of the email.
Subscribe to:
Posts (Atom)
