Cooking vs Chemistry

Chemistry is like cooking ... just don't lick the spoon.

Cooking can be used to help students understand fundamental chemical concepts, like chemical equations and stoichiometry.

Read how at https://www.ausetute.com.au/ausenews/ausenews.html

Chemical Equations for Equilibrium Reactions

 

When do you use single arrow → in a chemical equation and when do you use a double-headed arrow ⇌ in a chemical equation?

Go to https://www.ausetute.com.au/equilibriumeqtn.html to find out!

 

AUS-e-TUTE Members should log-in to use the new Writing Chemical Equations for Equilibrium Reactions tutorial, game, test and exam with worked solutions.

Classification of Organic Reactions

Organic reactions are reactions in which the reactants and products are carbon-containing compounds, or organic compounds.
The chemical reactions that organic compounds take part in can be classified as:

• substitution reactions
• addition reactions
• elimination reactions
• oxidation reactions
• reduction reactions
• polymerisation reactions
• rearrangement reactions

AUS-e-TUTE has just added new resources including  a tutorial, game and test with worked solutions to help you identify and classify these types of organic reactions. AUS-e-TUTE Members should log-in to use these new resources.

If you are not an AUS-e-TUTE, a free-to-view tutorial is currently available at https://www.ausetute.com.au/organicrxn.html

Properties of Nitriles

Why are the physical properties, such boiling point and solubility, of an alkanenitrile so similar to that of a primary alkanol with the same number of carbon atoms in the hydrocarbon chain?
Why do alkanenitriles react with so many different reactants?
AUS-e-TUTE has just added new resources to help you understand the physical and chemical properties or alkanenitriles.
AUS-e-TUTE Members should log-in to use the new tutorial, game and test (with worked solutions).
If you are not an AUS-e-TUTE Member you can access a "free-to-view" tutorial at https://www.ausetute.com.au/nitriles.html

Properties of Aldehydes and Ketones

Aldehydes and ketones contain the same functional group, for example, butanal and butanone both contain the same carbonyl functional group (C=O). So how would you tell if a substance was butanal or butanone?
AUS-e-TUTE has just added new resources to help you understand the similarities and differences in the chemical and physical properties of aldehydes and ketones (as represented by alkanals and alkanones). AUS-e-TUTE Members should log-in to use the new tutorial, game, test and exam with worked solutions.
If you are not an AUS-e-TUTE member there is currently a "free-to-view" tutorial on this topic at https://www.ausetute.com.au/ketones.html

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

Bleach

Lurking in my laundry cupboard is an opaque, plastic bottle containing bleach. I use it to whiten white clothes when they start to look a bit grey, but I also use it to clean blood stains, to remove mildew from walls and ceilings, and to remove the mould from bathroom tiles. The active ingredient in laundry bleach is sodium hypochlorite, NaOCl, and you will find a similar substance present in the "liquid chlorine" you add to swimming pools as a disinfectant.

Sodium hypochlorite is a very useful chemical, but it can also be dangerous if used incorrectly. 

The September 2018 issue of AUS-e-NEWS, AUS-e-TUTE's free quarterly newsletter for chemistry students and teachers, looks at the chemistry of bleach.

If you would like to subscribe to AUS-e-NEWS please go to https://www.ausetute.com.au/ausenews.html

Spontaneous Chemical Reactions

What makes a chemical reaction spontaneous?
If I add hydrochloric acid (HCl_(aq)) to metallic magnesium (Mg_(s)), bubbles of hydrogen gas (H_2(g)) are given off and the remaining solution contains chloride ions and magnesium ions (MgCl_2(aq)):

Mg_(s) + 2HCl_(aq) → H_2(g) + MgCl_2(aq)

But if I try to bubble hydrogen gas through an aqueous solution of magnesium chloride, nothing happens. No solid magnesium forms! Why?
AUS-e-TUTE has just added a new tutorial, game, test and exam to help you understand what makes a reaction spontaneous, nonspontaneous, reversible or irreversible.
AUS-e-TUTE Members should log-in to use these new resources (listed under Thermodynamics in the Physical Chemistry section).

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A "free-to-view" spontaneous reactions tutorial is currently available for evaluation purposes at:
http://www.ausetute.com.au/spontaneous.html

Gutful of Gas

People can eat interesting things.
In the 1960s in Australia, Leon Samson was eating razor blades to amuse audiences, he even started to eat, slowly, in bits, a car for a bet. A little later, France produced Michel Lotito who was also eating odd things to entertain us, including an airplane between 1978 and 1980.

A razor blade is made out of steel, a particular kind of steel known as razor blade steel. A 2.61 gram razor blade contains between about 13% chromium, 0.6% carbon, and  the rest is iron. Samson would chew up a razor blade and swallow it.

After leaving the mouth, the chewed-up bits of razor blade travel to the stomach. An empty stomach has a volume of about 75 mL but when we eat the volume of the stomach can expand out to about 1 L. Protein-digesting enzymes known as proteases are released into the stomach to help begin the break up of the proteins like you find in meat, fish, eggs and cheese. The optimum pH for these proteases is at about pH 2, so hydrochloric acid is also released into the stomach.

So the small bits of razor blade now find themselves surrounded by hydrochloric acid. Hydrochloric reacts with metals, like the iron in steel, to produce hydrogen gas. Now gases have an interesting property, they expand out to fill the available space. This suggests that eating razor blades might result in a feeling of being bloated. Thankfully, it appears that it takes about 24 hours for the complete reaction between a razor blade and hydrochloric acid in the stomach, plenty of time to remove the gas build-up via burping or, um, farting.

Hydrogen gas is commonly found in our intestines, along with other gases like carbon dioxide, oxygen and nitrogen. Some of these gases get there when we swallow air along with our food and drink, but they also come from chemical reactions inside our bodies. If our bodies are healthy and working well, all the usual gases will be present in the usual concentration, but if there is something wrong, if we are sick, the nature and composition of the gases will change.

Researchers at RMIT University in Melbourne, Australia, have developed and trialed an "ingestible electronic capsule" which is capable of sensing and measuring the gases in the gut like hydrogen, carbon dioxide and oxygen. These capsules offer a new, non-invasive way to monitor the health of our gut. The capsules can be collected after they have been excreted (apparently painlessly).

Reference: 
Kourosh Kalantar-Zadeh, Kyle J. Berean, Nam Ha, Adam F. Chrimes, Kai Xu, Danilla Grando, Jian Zhen Ou, Naresh Pillai, Jos L. Campbell, Robert Brkljača, Kirstin M. Taylor, Rebecca E. Burgell, Chu K. Yao, Stephanie A. Ward, Chris S. McSweeney, Jane G. Muir, Peter R. Gibson. A human pilot trial of ingestible electronic capsules capable of sensing different gases in the gut. Nature Electronics, 2018; 1 (1): 79 DOI: 10.1038/s41928-017-0004-x

Suggested Further Reading 
Experimental Design: http://www.ausetute.com.au/experimentd.html
Name and Formula of Binary Covalent Compounds: http://www.ausetute.com.au/namcform.html
Percentage Composition:  http://www.ausetute.com.au/percentc.html
Mass-moles Calculations: http://www.ausetute.com.au/massmole.html
Molar Gas Volume Calculations: http://www.ausetute.com.au/molarvol.html
Ideal Gas Law Calculations:  http://www.ausetute.com.au/idealgas.html
Metal + Non-Oxidising Acid Reaction: http://www.ausetute.com.au/metalhcl.html
Hydrogen Ion Concentration of Strong Acids: http://www.ausetute.com.au/hstronga.html 
Reaction Calculations: Mass and Moles http://www.ausetute.com.au/molreact.html 

Suggested Study Questions

1.   Design an experiment to determine how long it would take for a razor blade to react completely with the hydrochloric acid in the stomach. Investigate ways to speed up, or, to slow down, this reaction.
2. Give the formula for each of the following:
   • hydrogen gas
   • nitrogen gas
   • oxygen gas
   • carbon dioxide gas
   • hydrochloric acid
3.   Determine the percentage composition of each of the following compounds
   • hydrogen chloride gas
   • carbon dioxide gas
4. From the information in the article, calculate the mass of each of the following elements found in a razor blade:
   • iron
   • chromium
   • carbon
5. Using the information above, calculate the moles of each of the following elements found in a razor blade:
   • iron
   • chromium
   • carbon
6. Calculate the moles of hydrogen gas that occupy the entire volume of a "full" stomach under the following conditions:
   • 0^oC and 100 kPa
   • 25^oC and 100 kPa
   • 37^oC and 100 kPa
7. Write a balanced chemical equation for the reaction between the hydrochloric acid in the stomach and the iron in a razor blade.
8. Calculate the concentration of acid released into the stomach using the information in the article. 
9. Use the balanced chemical equation to determine the volume of hydrogen gas produced when all the iron in a razor blade has reacted with hydrochloric acid.
10. Consider all the information in the article, and the calculations you have performed so far. Explain why it takes 24 hours for a razor blade to be completely digested in the stomach.

Chemistry Rockets to Mars

NASA is developing the most powerful rocket in history, the Space Launch System (abbreviated to SLS) to launch the spacecraft known as Orion. Orion is expected to carry humans beyond the Moon and on to Mars in the 2030s.
It is well known that engineers, physicists, mathematicians and computer programmers play a quintessential part in the design, development, launch, trajectory and landing of rockets and spacecraft, but what about chemists?
Chemistry also plays an important role in getting rockets off the ground.
Without an understanding of chemistry there would be no fuel, no thrust, no take-off!

Read more in the December 2017 issue of AUS-e-NEWS.

To subscribe to AUS-e-NEWS got to http://www.ausetute.com.au/ausenews.html

Candle-lit Chemistry

What could be more romantic than a candle-lit dinner for two?

Good food, cosy conversation, and the gentle, flickering flames bathing everything in a warm glow.

And all this romance is delivered by the burning of a humble candle, a simple device made up of a block of solid fuel and a wick....

Learn more about the chemistry of candle light in the June 2016 edition of AUS-e-NEWS

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Reaction Schemes

When is a flow chart not a flow chart?
When it's a reaction scheme.
Want to learn about reaction schemes used in organic (carbon chemistry) ?
Good, because AUS-e-TUTE has just added a new tutorial, game, test, and exam to help you learn and understand.

AUS-e-TUTE Members should log-in to use the new resources.

If you are not an AUS-e-TUTE Members, there is a "free-to-view" tutorial currently available for evaluation purposes at:
http://www.ausetute.com.au/schemaorg.html

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