If you want to find the value of the acid dissociation constant for a weak acid you look up tables of values. For example, the value of Ka for acetic acid (ethanoic acid) is always tabulated.
But what if you want the value of a base dissociation constant? What if you want the value of Kb for the acetate ion (ethanoate ion)? You won't find this value in a table, you'll have to know how to calculate it!
AUS-e-TUTE has just added new resources to help you understand and apply the concept of acid and base hydrolysis including calculations. AUS-e-TUTE Members should log-in to access the new tutorial, game, test, exam (with worked solutions), and teacher members can access the worksheet wizard to make printable worksheets and quizzes (with answers).
If you are not an AUS-e-TUTE Member, the "free-to-view" tutorial is currently available at
https://www.ausetute.com.au/kakbkw.html
Friday, December 27, 2019
Sunday, December 15, 2019
Acid + Carbonate
Wednesday, December 4, 2019
Lithium-ion batteries
When you walk around having a chat to your friends on your mobile
phone, or watch a show on your tablet, or do your homework on your laptop in a
cosy cafe, have you ever stopped to wonder about the amazing revolution in
chemistry that allows you to do these "every day" things?
Batteries that are small, that can store enough electrical energy
so that they can be used continuously for hours, can be quickly recharged, and
can be discharged and recharged many, many times, are a very recent
development. Without these batteries your life-style would be a lot less
mobile!
What makes these batteries so special?
Find out in the December 2019 issue of AUS-e-NEWS
Sunday, November 24, 2019
acid + base
When an acid and a base are mixed together they react to produce a salt and water.
The general word equation for this type of acid-base reaction is:
The general word equation for this type of acid-base reaction is:
acid + base → salt + water
But can you write the word equation for the reaction between a specific acid, for example hydrochloric acid , and specific base, say sodium hydroxide?
AUS-e-TUTE is here to help!
We've just added new learning resources; a tutorial, game, test and exam to help our members write acid + base word equations. We even have a worksheet wizard that lets teachers make their own printable worksheet or quiz on this topic.
You can join AUS-e-TUTE today at https://www.ausetute.com.au/register.html
If you would like to a view a read-only tutorial for free, you can at https://www.ausetute.com.au/weacidbase.html
Saturday, November 9, 2019
acid + metal
When you add an acid to a metal you expect a chemical reaction to occur in which you produce a salt and hydrogen gas.
Your teacher expects you to be able to write a word equation to describe this chemical reaction.
AUS-e-TUTE has just added a new tutorial, game, test, and exam to help you write word equations for the chemical reaction between an acid and a metal.
AUS-e-TUTE Members should log-in to use these new resources.
If you are not a Member of AUS-e-TUTE, you can access the "free-to-view" tutorial : https://www.ausetute.com.au/weacidmetal.html
Your teacher expects you to be able to write a word equation to describe this chemical reaction.
AUS-e-TUTE has just added a new tutorial, game, test, and exam to help you write word equations for the chemical reaction between an acid and a metal.
AUS-e-TUTE Members should log-in to use these new resources.
If you are not a Member of AUS-e-TUTE, you can access the "free-to-view" tutorial : https://www.ausetute.com.au/weacidmetal.html
Thursday, October 24, 2019
World Teachers' Day
How would you describe your Chemistry teacher? Inspirational? Boring? Caring? A bully? Compassionate? Dedicated? Disinterested?
How would your Chemistry teacher describe you?
In common with all your other teachers, your Chemistry teacher's greatest desire is to inspire you and to help you achieve success in your studies. (Yes, I am serious!)
Your Chemistry teacher will be disappointed when you don't attempt your homework, hand in your lab reports and assessments on time, and when you are distracted in class or lack concentration. Your teacher will try to help you, sometimes this might feel like a teacher "picking on you", harassing you or bullying you, but your teacher just wants to get you focused and trying to do the work required to the best of your ability.
Teachers get frustrated when capable students don't submit work that reflects their abilities, and when students try to "look up" or "find" the answer rather than think through a problem and arrive at a solution through their own efforts. Teachers get excited when students "get it", when they achieve results better than expected, when they display interest, and when they try to solve problems through their own efforts (especially when the student finds the work difficult).
Teachers will make allowances for student "mis"-behaviour when they know you are not feeling well or are feeling stressed, when assessments are due, during exams, etc. But do you make similar allowances for your teacher's "mis"-behaviour ... yes... teachers get sick and stressed too (they are only human after all)! Assessments and exams to mark, reports to write, lessons to plan, whole teaching programs to revise and/or write, not to mention thinking about new ways to present concepts to students who have failed to understand them.
You are probably at school because you "need to be", you view it as a stepping-stone to your career goal or future aspirations. Have you ever wondered why your teacher is at school?
Your Chemistry teacher is at school because they want to share their love of Chemistry with you and to help you understand Chemistry so that you will also enjoy it and achieve the best results you can.
On International Teachers' Day, take a moment to think about how your Chemistry teacher might see you as a student, and, think about how you might help your teacher to help you.
International "World Teachers' Day" is held annually on the 5th October .... unless you are in Australia where this date usually falls in the school holidays, so the Australian version of "Teachers' Day" is held on the last Friday in October (25th October 2019).
How would your Chemistry teacher describe you?
In common with all your other teachers, your Chemistry teacher's greatest desire is to inspire you and to help you achieve success in your studies. (Yes, I am serious!)
Your Chemistry teacher will be disappointed when you don't attempt your homework, hand in your lab reports and assessments on time, and when you are distracted in class or lack concentration. Your teacher will try to help you, sometimes this might feel like a teacher "picking on you", harassing you or bullying you, but your teacher just wants to get you focused and trying to do the work required to the best of your ability.
Teachers get frustrated when capable students don't submit work that reflects their abilities, and when students try to "look up" or "find" the answer rather than think through a problem and arrive at a solution through their own efforts. Teachers get excited when students "get it", when they achieve results better than expected, when they display interest, and when they try to solve problems through their own efforts (especially when the student finds the work difficult).
Teachers will make allowances for student "mis"-behaviour when they know you are not feeling well or are feeling stressed, when assessments are due, during exams, etc. But do you make similar allowances for your teacher's "mis"-behaviour ... yes... teachers get sick and stressed too (they are only human after all)! Assessments and exams to mark, reports to write, lessons to plan, whole teaching programs to revise and/or write, not to mention thinking about new ways to present concepts to students who have failed to understand them.
You are probably at school because you "need to be", you view it as a stepping-stone to your career goal or future aspirations. Have you ever wondered why your teacher is at school?
Your Chemistry teacher is at school because they want to share their love of Chemistry with you and to help you understand Chemistry so that you will also enjoy it and achieve the best results you can.
On International Teachers' Day, take a moment to think about how your Chemistry teacher might see you as a student, and, think about how you might help your teacher to help you.
International "World Teachers' Day" is held annually on the 5th October .... unless you are in Australia where this date usually falls in the school holidays, so the Australian version of "Teachers' Day" is held on the last Friday in October (25th October 2019).
Saturday, October 19, 2019
Naming Nitriles
How do you name a molecule like H-C≡N?
If you are an inorganic chemist you might call it:
AUS-e-TUTE has a new tutorial, game and test to help our members understand and apply IUPAC naming rules to nitriles. Members should log-in to use these new resources.
If you are not a member of AUS-e-TUTE you can access a "free-to-view" tutorial on naming nitriles at https://www.ausetute.com.au/namnitrile.html
If you are an inorganic chemist you might call it:
- hydrogen cyanide (hydrogen name)
- hydridonitridocarbon (additive name)
- methylidyneazane (substitutive name)
- hydrogen cyanide (functional class name)
- formonitrile (preferred IUPAC name)
- methanenitrile (substitutive name)
AUS-e-TUTE has a new tutorial, game and test to help our members understand and apply IUPAC naming rules to nitriles. Members should log-in to use these new resources.
If you are not a member of AUS-e-TUTE you can access a "free-to-view" tutorial on naming nitriles at https://www.ausetute.com.au/namnitrile.html
Monday, October 14, 2019
Hydrogen Emission Spectrum
How many lines are in the emission spectrum of hydrogen?
Where do these lines come from?
What are the Lyman, Balmer, Paschen, Brackett, Pfund and Humphreys Series?
Find the answers to these questions and more in AUS-e-TUTE's new hydrogen emission spectrum resources.
AUS-e-TUTE Members should log-in to access the new tutorial, game, test and exam (with worked solutions of course!)
If you are not an AUS-e-TUTE member you can access a "free-to-view" Hydrogen Emission Spectrum tutorial at https://www.ausetute.com.au/hspectrum.html
Where do these lines come from?
What are the Lyman, Balmer, Paschen, Brackett, Pfund and Humphreys Series?
Find the answers to these questions and more in AUS-e-TUTE's new hydrogen emission spectrum resources.
AUS-e-TUTE Members should log-in to access the new tutorial, game, test and exam (with worked solutions of course!)
If you are not an AUS-e-TUTE member you can access a "free-to-view" Hydrogen Emission Spectrum tutorial at https://www.ausetute.com.au/hspectrum.html
Saturday, September 28, 2019
Periodic Table Challenge
2019 is the International Year of the Periodic Table and IUPAC has a game you can play online!
Here is the link https://iupac.org/100/pt-challenge/
Before you can play, you need to choose an avatar (an element ofcourse!).
Now I don't want to influence your decision in anyway, but ..... the ONLY element named after a woman is Meitnerium, Mt, after Lise Meitner (Curium is named after the wife and husband team of Marie and Pierre Curie).
There are 15 multiple choice questions to answer.
Complete the quiz and generate your certificate.
Get 9 or more correct answers and you get the chance to enter the Nobelium Contest with a chance to win a limited edition Periodic Table autographed by a Nobel Laureate in Chemistry.
The questions are really interesting. Here is a sample..
Here is the link https://iupac.org/100/pt-challenge/
Before you can play, you need to choose an avatar (an element ofcourse!).
Now I don't want to influence your decision in anyway, but ..... the ONLY element named after a woman is Meitnerium, Mt, after Lise Meitner (Curium is named after the wife and husband team of Marie and Pierre Curie).
There are 15 multiple choice questions to answer.
Complete the quiz and generate your certificate.
Get 9 or more correct answers and you get the chance to enter the Nobelium Contest with a chance to win a limited edition Periodic Table autographed by a Nobel Laureate in Chemistry.
The questions are really interesting. Here is a sample..
- In the 1920s, many companies promoted their products by adding radium. One of the top-selling radium-containing products was 'Radithor'. What was it?
- In the 1880s, Lord Rayleigh found that the density of nitrogen from air was 0.5% greater than the density of nitrogen obtained from other sources. What discovery resulted from this small discrepancy?
- The 1944 American film ‘Arsenic and Old Lace’, starring Cary Grant, features what use of this chemical element?
- Despite having few uses, erbium has one very important use that makes it beneficial to the modern world. Which one?
- Whereas in humans oxygen is bound to iron-containing haemoglobin, spiders and other animals transport oxygen via a different protein in their blood, hemocyanin, which contains copper. What is the color of their blood?
What happens when a teaspoon made of gallium is used to stir a cup of warm tea?
The atomic weight of argon varies depending on its source. What is the reason for this phenomenon?
Vincent van Gogh’s painting Sunflowers is getting darker due to the presence of chromium in the paint. What is the chemistry behind this change in appearance?
When tellurium is absorbed through the skin, it is excreted through sweat as hydrogen telluride making you unfit for social interactions. Why?
Indium is mostly used to make indium tin oxide which is an important part of touchscreens. How did indium get its name?
What name was proposed for bromine by its discoverer, the French scientist Antoine Balard?
Monday, September 23, 2019
Polypropene
Polypropene is one of the most widely used plastics in the world.
What is it? How do you make it? What properties does it have? What is it used for?
AUS-e-TUTE has just added a new tutorial, game, test, and exam for our members to help them understand polypropene, and apply that knowledge to answering test and exam questions.
AUS-e-TUTE Members should log-in to use these new resources.
If you are not an AUS-e-TUTE Member you can access a free-to-view tutorial for evaluation purposes at https://www.ausetute.com.au/polypropene.html
What is it? How do you make it? What properties does it have? What is it used for?
AUS-e-TUTE has just added a new tutorial, game, test, and exam for our members to help them understand polypropene, and apply that knowledge to answering test and exam questions.
AUS-e-TUTE Members should log-in to use these new resources.
If you are not an AUS-e-TUTE Member you can access a free-to-view tutorial for evaluation purposes at https://www.ausetute.com.au/polypropene.html
Thursday, September 5, 2019
Micellar Water
Once upon a time you would buy a bar of soap and use it to wash your hands,
face, body, and possibly even your hair.
Not today! Now you have hand-wash for your hands, body-wash for your body, shampoo for your hair, and a huge range of different products to clean your face including "micellar water" or "micellar cleansing water".
Unlike other face-cleaning products which need to be washed off with water, the makers of "micellar water" claim that it will cleanse your skin without vigorous rubbing or rinsing.
Intriguing! This "micellar water" sounds like some kind of magic doesn't it?
What's in "micellar water" and how does it work?
Read all about it in the September 2019 edition of AUS-e-NEWS, AUS-e-TUTE's free quarterly newsletter for chemistry students and teachers.
Not today! Now you have hand-wash for your hands, body-wash for your body, shampoo for your hair, and a huge range of different products to clean your face including "micellar water" or "micellar cleansing water".
Unlike other face-cleaning products which need to be washed off with water, the makers of "micellar water" claim that it will cleanse your skin without vigorous rubbing or rinsing.
Intriguing! This "micellar water" sounds like some kind of magic doesn't it?
What's in "micellar water" and how does it work?
Read all about it in the September 2019 edition of AUS-e-NEWS, AUS-e-TUTE's free quarterly newsletter for chemistry students and teachers.
Want to subscribe to AUS-e-NEWS?
Tuesday, August 13, 2019
polytetrafluoroethene
Polytetrafluoroethene is a very useful polymer. You can can find it encasing electrical wires, being sprayed out of a can of lubricant, and as the non-stick covering on your baking tray. So what is this remarkable polymer? How is it made? What are its properties and uses?
Find out the answers to these and other questions at AUS-e-TUTE.
AUS-e-TUTE members should log-in to view the polytetrafluoroethene tutorial, play the game and take the test and exam.
If you are not a member, you can access a "free-to-view" tutorial at https://www.ausetute.com.au/ptfe.html
Find out the answers to these and other questions at AUS-e-TUTE.
AUS-e-TUTE members should log-in to view the polytetrafluoroethene tutorial, play the game and take the test and exam.
If you are not a member, you can access a "free-to-view" tutorial at https://www.ausetute.com.au/ptfe.html
Saturday, August 10, 2019
Science Week 2019
Did you know it's Science Week in Australia (10th to 18th August 2019)
This year's theme is "Destination Moon: more missions, more science"
You can find events near you at https://www.scienceweek.net.au/
There is a downloadable pdf of classroom ideas available (https://www.scienceweek.net.au/wp-content/uploads/2019/02/2019ASTA-DestinationMoon_ResourceBook.pdf)
This year's theme is "Destination Moon: more missions, more science"
You can find events near you at https://www.scienceweek.net.au/
There is a downloadable pdf of classroom ideas available (https://www.scienceweek.net.au/wp-content/uploads/2019/02/2019ASTA-DestinationMoon_ResourceBook.pdf)
Thursday, August 8, 2019
How to Maximise Marks in Your Chemistry Exam
Are you ready for your chemistry exam?
The Sydney Morning Herald provided 8 dot points to help you answer Chemistry exam questions, which we have expanded out below:
The Sydney Morning Herald provided 8 dot points to help you answer Chemistry exam questions, which we have expanded out below:
- Write correctly balanced equations.(Include state, or phase, of matter)
- Structure your answers to ensure they are logical. Written calculations should be neatly organised and sequential.
- If you dilute an acid with water at 25°C, the pH of the solution will not rise above 7
- If you dilute a base with water at 25°C, the pH of the solution will not fall below 7
- Clearly label your graphs (plots, scale, axis, line of best fit).
- Use relevant scientific terminology.
- Check your spelling! Ethane is NOT the same as ethene! Molarity is NOT the same as morality! Calorimetry is NOT the same as colorimetry!
- If the question is about physical properties, think about intermolecular forces.
- If the question is about chemical properties, think about intramolecular forces, and think about types of chemical reactions for inorganic chemicals and for organic chemicals (combustion, addition, substitution, elimination, condensation, polymerisation)
- Explain the underlying chemistry and provide relevant chemical equations.
- Is it a gas question? Ideal Gas Law? Molar Volume?
- Precipitation question? Solubility Rules? Solubility Product? Gravimetric Analysis? Conductometric Analysis? Argentimetric Analysis?
- Equilibrium question? Equilibrium concepts? Le Chatelier's Principle? Equilibrium law?
- Acid/base question? Definitions? Properties? Acid strength? Acid-dissociation constant? Neutralisation reaction? Titration techniques? Titration calculations?
- Chemical kinetics question? Reaction rate? Maxwell-Boltzmann distribution?
- Determination of organic structure? C-13 NMR, Mass Spectroscopy? IR Sopectroscopy?
- Use subscripts and superscripts where appropriate.
- Formula of ions, superscript to right of symbol (number first followed by sign)
- Formula of isotopes, mass number superscript to left of symbol, atomic number subscript to left of symbol
- Molecular formula or empirical formula, number of atoms of each element shown as a subscript to the right of the element's symbol
- "States" or "phases" of matter are sometimes written as a subscript to the right of a molecular formula, eg, CO2(g), but are usually written in line with with formula, eg, CO2(g)
- Use stimulus materials to answer the question.
- Use clear labels when continuing responses in a different booklet.
Friday, July 26, 2019
Gold Nuggets in 2019
Between 1850 and 1900, the city of Bendigo in Victoria, Australia, was the centre of a Gold Rush. Central Deborah Gold Mine, the last commercial gold mine to operate in Bendigo, re-opened as a tourist attraction in 1986.
Gold can still be found in the Bendigo area.
On Mothers' Day 2019, a family out walking Lucky their dog on the outskirts of Bendigo walked onto a gold nugget. They took it along to the local IGA supermarket to weigh it. The gold nugget weighed 624 grams (about 20 ounces).
Today, the price of gold in Australia is listed as $65.76 per gram. So, if pure, the gold in this nugget would be worth 624 × $65.76 ≈ $41,000.
How big would this gold nugget be?
We know the mass of the nugget is 624 grams.
We can look up the density of gold in tables, ρ = 19.3 g cm-3
Since density = mass (g) ÷ volume (cm3)
19.3 = 624 ÷ volume (cm3)
volume (cm3) = 624 g ÷ 19.3 g cm-3 = 32.3 cm3
Which could be represented by a cube approximately 3.2 cm × 3.2 cm × 3.2 cm
Not very big at all is it!
Ballarat, another Victorian Gold Rush town and site of the historic "Eureka Stockade", was also the place where another spectacular gold nugget was found in June 2019 (and reported nationally in July 2019). This gold nugget weighed about 2 kilograms, or 2,000 grams.
At today's prices, it would have a value of about 2,000 × $65.76 ≈ $130,000
And how big would this nugget be?
density = mass (g) ÷ volume (cm3) volume (cm3)
density = mass (g) ÷ density (g cm-3) = 2,000 g ÷ 19.3 g cm-3 = 103.6 cm3
The dimensions of a cube with this volume would be about 4.7 cm × 4.7 cm × 4.7 cm
Which would fit nicely into the palm of your hand as shown in the photograph below
Further Reading:
Density Calculations
Suggested Study Questions:
Gold can still be found in the Bendigo area.
On Mothers' Day 2019, a family out walking Lucky their dog on the outskirts of Bendigo walked onto a gold nugget. They took it along to the local IGA supermarket to weigh it. The gold nugget weighed 624 grams (about 20 ounces).
Today, the price of gold in Australia is listed as $65.76 per gram. So, if pure, the gold in this nugget would be worth 624 × $65.76 ≈ $41,000.
How big would this gold nugget be?
We know the mass of the nugget is 624 grams.
We can look up the density of gold in tables, ρ = 19.3 g cm-3
Since density = mass (g) ÷ volume (cm3)
19.3 = 624 ÷ volume (cm3)
volume (cm3) = 624 g ÷ 19.3 g cm-3 = 32.3 cm3
Which could be represented by a cube approximately 3.2 cm × 3.2 cm × 3.2 cm
Not very big at all is it!
Ballarat, another Victorian Gold Rush town and site of the historic "Eureka Stockade", was also the place where another spectacular gold nugget was found in June 2019 (and reported nationally in July 2019). This gold nugget weighed about 2 kilograms, or 2,000 grams.
At today's prices, it would have a value of about 2,000 × $65.76 ≈ $130,000
And how big would this nugget be?
density = mass (g) ÷ volume (cm3) volume (cm3)
density = mass (g) ÷ density (g cm-3) = 2,000 g ÷ 19.3 g cm-3 = 103.6 cm3
The dimensions of a cube with this volume would be about 4.7 cm × 4.7 cm × 4.7 cm
Which would fit nicely into the palm of your hand as shown in the photograph below
Further Reading:
Density Calculations
Suggested Study Questions:
- The density of gold is 19.3 g cm-3. Calculate the mass of
- 1 cm3 of gold
- 10 cm3 of gold
- 1 m3 of gold
- The density of gold is 19.3 g cm-3. Calculate the volume of
- 1 g of gold
- 10 g of gold
- 1 kg of gold
- The density of gold is 19.3 g cm-3. Calculate the dimensions of a cube of gold which has a mass of
- 5 g
- 500 g
- 5 kg
- The density of gold is 19.3 g cm-3. Calculate the diameter of a sphere of gold which has a mass of
- 2 g
- 200 g
- 2 kg
- A credit card has the approximate dimensions 65 mm × 55 mm × 1 mm. Calculate:
- volume of the credit card in cm3
- mass of a gold credit card
- value of a gold credit card if the cost of gold is $65 per gram
- Why aren't "gold" credit cards really made out of gold?
- Gold is one of the few metals that is found in nature as the "native" element (that is, it is found as the element and not in compounds). Explain why gold can be found in nuggets.
- Name some other metals that can also be found in their native state (that is, found as the element and not as compounds). Explain why these metals can be found in their native state.
- Name a metal that is not found on Earth in its native state, and explain why it is not found in nature as the uncombined element.
Sunday, July 21, 2019
Word Equations for Chemical Reactions
A word equation is Chemistry short-hand for describing how new substances can be made using an initial substance (or substances).
The initial substances are called reactants.
The new substances formed are called products.
The most general form of a word equation is:
The initial substances are called reactants.
The new substances formed are called products.
The most general form of a word equation is:
reactants → products
AUS-e-TUTE has just added a new tutorial, game and test to help our members understand and use word equations. Members should log-in to the Test Centre to use these resources.
A "free-to-view" tutorial on word equations is currently available for non-members to access at
Join AUS-e-TUTE today to start solving chemistry problems, and getting feedback, to help you understand and apply chemistry concepts.
Sunday, July 14, 2019
Glycaemic Index
Low GI food or high GI food?
What is GI?
How is it measured?
What does it mean?
These are many other questions are addressed in AUS-e-TUTE's new glycaemic index (GI) resources.
AUS-e-TUTE Members should log-in to access the new tutorial, game, test and exam.
If you are not an AUS-e-TUTE Member you can access a "free-to-view" tutorial for evaluation purposes at https://www.ausetute.com.au/glycaemic.html
What is GI?
How is it measured?
What does it mean?
These are many other questions are addressed in AUS-e-TUTE's new glycaemic index (GI) resources.
AUS-e-TUTE Members should log-in to access the new tutorial, game, test and exam.
If you are not an AUS-e-TUTE Member you can access a "free-to-view" tutorial for evaluation purposes at https://www.ausetute.com.au/glycaemic.html
Saturday, June 29, 2019
Hydrolysis of Proteins
Lots of foods contain protein. When you eat them the proteins undergo hydrolysis reactions to break them down into their constituent amino acids.
AUS-e-TUTE has just added a new tutorial, game, test and exam to help you understand this.
AUS-e-TUTE Members should log-in to use these new resources (listed under Biochemical Reactions).
Non-members can currently access a "free-to-view" tutorial at
https://www.ausetute.com.au/hydrolysisprot.html
AUS-e-TUTE has just added a new tutorial, game, test and exam to help you understand this.
AUS-e-TUTE Members should log-in to use these new resources (listed under Biochemical Reactions).
Non-members can currently access a "free-to-view" tutorial at
https://www.ausetute.com.au/hydrolysisprot.html
Monday, June 24, 2019
Hydrolysis of Carbohydrates
Carbohydrates like disaccharides and polysaccharides can be broken down into monosaccharides.
In the lab we use acid hydrolysis, but in your body you use enzymes to do this.
AUS-e-TUTE has just added a new tutorial, game, test and exam to help you understand these chemical reactions. Members should log-in to access these new resources (under Biochemical reactions).
If you are not an AUS-e-TUTE member you can access a "free-to-view" tutorial at https://www.ausetute.com.au/hydrolysiscarbs.html
In the lab we use acid hydrolysis, but in your body you use enzymes to do this.
AUS-e-TUTE has just added a new tutorial, game, test and exam to help you understand these chemical reactions. Members should log-in to access these new resources (under Biochemical reactions).
If you are not an AUS-e-TUTE member you can access a "free-to-view" tutorial at https://www.ausetute.com.au/hydrolysiscarbs.html
Thursday, June 20, 2019
Precipitation Titrations
Have you ever tried to determine the chloride concentration in a water sample using gravimetric analysis? It's pretty tricky! There must be a better way .....
There is .... precipitation titrations (also known as argentimetric titrations or argentometric titrations).
AUS-e-TUTE has just added a new tutorial, game, test, exam and practical activity on this topic for members.
If you are not a member, you can access a "free-to-view" tutorial at
https://www.ausetute.com.au/pptitration.html
There is .... precipitation titrations (also known as argentimetric titrations or argentometric titrations).
AUS-e-TUTE has just added a new tutorial, game, test, exam and practical activity on this topic for members.
If you are not a member, you can access a "free-to-view" tutorial at
https://www.ausetute.com.au/pptitration.html
Thursday, June 13, 2019
Precipitation Conductometric Titrations
If you have an aqueous salt solution it conducts electricity because of all the ions in the solution. If you add a different aqueous salt solution to this it is possible that a precipitate will form, effectively removing some of the ions in solution so it should be possible to monitor changes in the electrical conductivity of a solution during a precipitation reaction to determine the equivalence point of the reaction. This is known as a precipitation conductometric titration (or as a conductometric precipitation titration) and AUS-e-TUTE has just added a new tutorial, game, test and exam to help our members understand this!
If you are not an AUS-e-TUTE Member, you can currently access a "free-to-view" tutorial on this topic at https://www.ausetute.com.au/conductpptn.html
If you are not an AUS-e-TUTE Member, you can currently access a "free-to-view" tutorial on this topic at https://www.ausetute.com.au/conductpptn.html
Sunday, June 9, 2019
Conductometric Titrations
Trying to titrate a weak acid with a weak base using an acid-base indicator is .... annoying!
The end point of the titration is extremely difficult to guage.
If only there was a better way ....
There is!
Let us introduce you to acid-base conductometric titrations in AUS-e-TUTE's new tutorial, game, test and exam resources. AUS-e-TUTE Members should log-in to use these new resources.
Non-members can currently access the "free-to-view" tutorial at https://www.ausetute.com.au/conductab.html
The end point of the titration is extremely difficult to guage.
If only there was a better way ....
There is!
Let us introduce you to acid-base conductometric titrations in AUS-e-TUTE's new tutorial, game, test and exam resources. AUS-e-TUTE Members should log-in to use these new resources.
Non-members can currently access the "free-to-view" tutorial at https://www.ausetute.com.au/conductab.html
Wednesday, June 5, 2019
Colorimetry
I was sitting with some friends drinking tea in glasses.
I noticed some people like "weak" tea and others like their tea "strong".
Technically "weak" tea isn't "weak" at all ... it's really a more dilute solution of tea, while "strong" tea is a more concentrated solution of tea.
But what I noticed most is that "weak" tea is less of a brown colour than "strong" tea, so it ought to be possible to guess the concentration of "tea" in a glass of tea by looking at its colour.
However, I wouldn't have to guess the concentration if I had a colorimeter because a colorimeter would measure the absorbance of each tea solution.
It may seem like a lot of hard work for very little reward ... "I'll like a 0.341 absorbance glass of tea please..." .... but colorimetry is useful tool for measuring the concentration of coloured solutions as you will find out in AUS-e-TUTE's new set of colorimetry resources.
AUS-e-TUTE Members should log-in to use the colorimetry resources listed under "Spectroscopy" and the subheading "Absorption Spectroscopy".
Non-members can access a "free-to-view" tutorial at https://www.ausetute.com.au/colorimetry.html
I noticed some people like "weak" tea and others like their tea "strong".
Technically "weak" tea isn't "weak" at all ... it's really a more dilute solution of tea, while "strong" tea is a more concentrated solution of tea.
But what I noticed most is that "weak" tea is less of a brown colour than "strong" tea, so it ought to be possible to guess the concentration of "tea" in a glass of tea by looking at its colour.
However, I wouldn't have to guess the concentration if I had a colorimeter because a colorimeter would measure the absorbance of each tea solution.
It may seem like a lot of hard work for very little reward ... "I'll like a 0.341 absorbance glass of tea please..." .... but colorimetry is useful tool for measuring the concentration of coloured solutions as you will find out in AUS-e-TUTE's new set of colorimetry resources.
AUS-e-TUTE Members should log-in to use the colorimetry resources listed under "Spectroscopy" and the subheading "Absorption Spectroscopy".
Non-members can access a "free-to-view" tutorial at https://www.ausetute.com.au/colorimetry.html
Friday, May 31, 2019
24 Carat Chemistry
I was trying to buy a present for my mum for Mothers' Day.
"A gold chain," I thought, "would be a nice present". But
when I got to the jewellery shop I found that there is a huge variety of
"gold chains", 24 carat gold, 18 carat gold, 9 carat gold, 995, 750,
375, white gold, rose gold...
Subscribe to AUS-e-TUTE's free quarterly newsletter at https://www.ausetute.com.au/ausenews.html
So what is a carat?
What do those numbers mean?
How can "gold" be different colours?
What do those numbers mean?
How can "gold" be different colours?
Read all about it in the June 2019 issue of AUS-e-NEWS
Thursday, May 9, 2019
Nanocellulose Foam
You have probably held polystyrene cups (styrofoam cups) in your hands. It is a wonderful material for making disposable cups because it is light-weight, holds it shape well, and is an excellent insulator. All this means that you can fill a polystyrene cup with hot tea and drink from it without having it burn your hands. High school chemistry teachers are very fond of using polystyrene cups as "cup calorimeters" in the school laboratory. Unfortunately, polystyrene is not an environmentally friendly polymer, it doesn't break down, it is chemically inert, so persists in the environment.
Plant-based polymers which degrade in time, such as cellulose, could replace polystyrene if we can make a cellulose-based material with same properties as polystyrene.
Cellulose is a polysaccharide. It is composed of many glucose units joined together by ether bonds (glycosidic links). During acid hydrolysis these ether bonds (glycosidic links) are attacked and broken so that the final product of a complete reaction is a lot of glucose molecules. The reaction mechanism for the acid hydrolysis of cellulose is shown below:
If only some of the ether bonds (glycosidic links) within a cellulose polymer chain are attacked, then you could end up with shorter chains of glucose polymer, still enough glucose units in the chain to be considered cellulose. If these chains are only 5-20 nanometres wide (even though they may be several micrometres long) they will be referred to as nanocellulose.
Researchers at Washington State University have added polyvinyl alcohol, shown below:
to nanocellulose. Polyvinyl alcohol binds to the nanocellulose which stabilises the foam that can be produced. This light-weight material is reported to be a better insulator than polystyrene foam (styrofoam) and "can support up to 200 times its weight without changing shape. It degrades well, and burning it doesn't produce polluting ash."
Suggested Further Reading:
Nanotechnology
Suggested Study Questions:
Plant-based polymers which degrade in time, such as cellulose, could replace polystyrene if we can make a cellulose-based material with same properties as polystyrene.
Cellulose is a polysaccharide. It is composed of many glucose units joined together by ether bonds (glycosidic links). During acid hydrolysis these ether bonds (glycosidic links) are attacked and broken so that the final product of a complete reaction is a lot of glucose molecules. The reaction mechanism for the acid hydrolysis of cellulose is shown below:
If only some of the ether bonds (glycosidic links) within a cellulose polymer chain are attacked, then you could end up with shorter chains of glucose polymer, still enough glucose units in the chain to be considered cellulose. If these chains are only 5-20 nanometres wide (even though they may be several micrometres long) they will be referred to as nanocellulose.
Researchers at Washington State University have added polyvinyl alcohol, shown below:
Suggested Further Reading:
Nanotechnology
Suggested Study Questions:
- Convert the following measurements to metres (m):
- 5 nm
- 20 nm
- 100 μm
- 1000 μm
- Convert the following measurements to nanometres (nm)
- 5 × 10-9 m
- 2.5 μm
- 5.2 mm
- 0.75 cm
- Draw a section of cellulose polymer containing 6 glucose units. Circle the ether bonds (glycosidic links) in red.
- Draw the results of acid hydrolysis if all the ether bonds (glycosidic links) in this section of cellulose polymer were broken.
- Draw the results of acid hydrolysis on the section of cellulose polymer you drew for question 3 if only 2 new "molecules" are produced. Is there only one possible answer? If more than one answer is possible, how many possible answers can you think of?
- Consider the structure of cellulose and of polyvinyl alcohol. Explain how polyvinyl alcohol can "bind with" cellulose.
- Explain why a nanocellulose foam can be stabilised by adding polyvinyl alcohol.
- Consider the combustion of cellulose. Give the products for
- complete combustion of cellulose
- incomplete combustion of cellulose
- Wood is composed largely of cellulose. When a wood log burns on a camp fire it produces a sooty flame. Explain why.
- Explain why nanocellulose is unlikely to produce a sooty flame when it burns.
Monday, April 15, 2019
Breaking Triglycerides up into Fatty Acids
Triglycerides are found in the fats and oils you eat. They are produced in a condensation reaction between a glycerol and 3 fatty acids. So, is it possible to reverse this reaction? Can we add water to a triglyceride to break it up into glycerol and 3 fatty acids?
Good question!
AUS-e-TUTE has new resources to help you understand the hydrolysis of triglycerides.
Members should log in to access the new tutorial, game, test and exam (with worked solutions).
If you are not an AUS-e-TUTE Member, you can access the "free-to-view" tutorial at
https://www.ausetute.com.au/hydrolysistg.html
Good question!
AUS-e-TUTE has new resources to help you understand the hydrolysis of triglycerides.
Members should log in to access the new tutorial, game, test and exam (with worked solutions).
If you are not an AUS-e-TUTE Member, you can access the "free-to-view" tutorial at
https://www.ausetute.com.au/hydrolysistg.html
Friday, April 12, 2019
Omega Fatty Acids
"Health Food" companies are always trying to sell us something new.
Instead of eating tasty fish they recommend we consume fish oil wrapped in plastic as a pill. Apparently this is because we are suddenly deficient in "omega-3 fatty acids".
So what are omega-3 fatty acids?
Where do they come from?
Do we really need them?
AUS-e-TUTE Members should log-in to access the new omega fatty acid resources (tutorial, game, test, exam).
If you are not an AUS-e-TUTE Member you can access a free-to-view tutorial at
https://www.ausetute.com.au/omegafat.html
Instead of eating tasty fish they recommend we consume fish oil wrapped in plastic as a pill. Apparently this is because we are suddenly deficient in "omega-3 fatty acids".
So what are omega-3 fatty acids?
Where do they come from?
Do we really need them?
AUS-e-TUTE Members should log-in to access the new omega fatty acid resources (tutorial, game, test, exam).
If you are not an AUS-e-TUTE Member you can access a free-to-view tutorial at
https://www.ausetute.com.au/omegafat.html
Sunday, April 7, 2019
Hydroxyacid or Carboxyalkanol?
So, you've learnt how to name organic molecules containing the OH (hydroxy) functional group, and, you can name molecules that have the COOH (carboxyl) functional group, the carbonyl functional group (C=O), and the NH2 (amine) functional group.
Excellent!
But what happens when there are 2 or more different functional groups on the same molecule?
Can you still name it?
We can help!
AUS-e-TUTE has just added a new tutorial, game, test and exam to help you learn the IUPAC rules and confidently apply them to these sorts of molecules.
AUS-e-TUTE Members should log-in to use the new resources (under Organic Nomenclature).
If you are not an AUS-e-TUTE Member you can view the tutorial for free at
https://www.ausetute.com.au/nam2fung.html
Excellent!
But what happens when there are 2 or more different functional groups on the same molecule?
Can you still name it?
We can help!
AUS-e-TUTE has just added a new tutorial, game, test and exam to help you learn the IUPAC rules and confidently apply them to these sorts of molecules.
AUS-e-TUTE Members should log-in to use the new resources (under Organic Nomenclature).
If you are not an AUS-e-TUTE Member you can view the tutorial for free at
https://www.ausetute.com.au/nam2fung.html
Thursday, April 4, 2019
Types of Structural Isomerism
If molecules have the same molecular formula but different structural formulae then they are called structural isomers and are said to display structural isomerism.
But there are different types of structural isomerism:
AUS-e-TUTE Members should log-in to use the new tutorial, game and test.
If you are not an AUS-e-TUTE member yet, you can view a tutorial for free at https://www.ausetute.com.au/isomerism.html
But there are different types of structural isomerism:
- chain isomerism (also known as skeletal isomerism)
- position isomerism (also known as regioisomerism)
- functional group isomerism (functional isomerism)
AUS-e-TUTE Members should log-in to use the new tutorial, game and test.
If you are not an AUS-e-TUTE member yet, you can view a tutorial for free at https://www.ausetute.com.au/isomerism.html
Sunday, March 31, 2019
How long is a piece of string?
How long is a piece of string?
What units of length you use to measure a piece of string will depend on how long the string is.
If you are putting up a string of Christmas lights you might measure the length of the string in metres or centimetres.
But if you are measuring the length of string, or ribbon, to tie back your hair you might measure the length of string in centimetres or millimetres.
1 centimetre is a hundredth of a metre: 1 cm = 10-2 m
1 millimetre is a thousandth of a metre: 1mm = 10-3 m
The metre is the SI base unit of length.
On the other hand, if your piece of string is holding 2 atoms together in a molecule you are going to need a very tiny piece of string, less than a billionth of a metre. Which is why chemists use units of length like the nanometre (1nm = 10-9 m), the Ångstrom (1 Å = 10-10 m), and the picometre (1 pm = 10-12 m).
You will need to be familiar with these units and be able to convert one unit of length into another, so AUS-e-TUTE has just added new tutorials, games, tests to help our members do this.
If you are not a member, you can access a "free-to-view" tutorial at https://www.ausetute.com.au/lengthconv.html
What units of length you use to measure a piece of string will depend on how long the string is.
If you are putting up a string of Christmas lights you might measure the length of the string in metres or centimetres.
But if you are measuring the length of string, or ribbon, to tie back your hair you might measure the length of string in centimetres or millimetres.
1 centimetre is a hundredth of a metre: 1 cm = 10-2 m
1 millimetre is a thousandth of a metre: 1mm = 10-3 m
The metre is the SI base unit of length.
On the other hand, if your piece of string is holding 2 atoms together in a molecule you are going to need a very tiny piece of string, less than a billionth of a metre. Which is why chemists use units of length like the nanometre (1nm = 10-9 m), the Ångstrom (1 Å = 10-10 m), and the picometre (1 pm = 10-12 m).
You will need to be familiar with these units and be able to convert one unit of length into another, so AUS-e-TUTE has just added new tutorials, games, tests to help our members do this.
If you are not a member, you can access a "free-to-view" tutorial at https://www.ausetute.com.au/lengthconv.html
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