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

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

Indicators and End Points

What colour is an indicator at the end point ?
At what pH does an indicator change colour?
Why is the colour change for an indicator always given as a range of pH values?

These questions are all addressed in AUS-e-TUTE's new Indicator End Point resources.
Read the tutorial, play the game, do the test and view worked solutions for the questions.

Not an AUS-e-TUTE Member?
There is currently a free-to-view tutorial available at http://ausetute.com.au/endpoint.html

Want to find out more about how an AUS-e-TUTE Membership will help you improve your understanding of chemistry, and, improve your exam results?
Then go to http://ausetute.com.au/membership.html

Ready to join AUS-e-TUTE ?
Go to http://ausetute.com.au/register.html

Got questions?
Contact us at http://ausetute.com.au/contact.html

Titration Techniques

What piece of glassware should you use to make a standard solution?
What should you rinse a burette with before filling it with solution?
Should you force all the solution out of a pipette when you use it?

These and many other questions about Titration Techniques have been addressed in AUS-e-TUTE's new tutorials, games, tests, and exams.

Members should log in to use all these new resources which are listed under Volumetric Analaysis, or, use the links from your Syllabus Study Guide in the Members Only Test Centre.

A "free-to-view" tutorial on titration techniques is currently available for evaluation purposes for non-members: http://ausetute.com.au/titrtech.html

Standard Solutions

What is the difference between a primary standard and a secondary standard in volumetric analysis?
What substances can be used as a primary standard?
How do you make a standard solution?

All these questions are answered in AUS-e-TUTE's new tutorial on standard solutions.
Members should log-in and go to the Volumetric Analysis section on the index page, or,
follow the links from your Chemistry syllabus study guide.
Members will also find a game, test and exam as well as tutorial on this topic.
Teachers will find  a worksheet wizard which will let you make, and print off, a worksheet on this topic.

Not an AUS-e-TUTE Member?
There is currently a "free-to-view" tutorial at http://www.ausetute.com.au/titrstand.html

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.

Why Use a Volumetric Flask?

In order to prepare an aqueous standard solution, you transfer the solute to a volumetric flask and then you add water "up to the mark", that is, until the bottom of the meniscus lies on the "mark" when viewed at eye-level. You can quickly convince yourself of the need to view the "mark" at eye-level just be preparing your standard solution as above and then changing the angle you view it from.
But what about this need to add water to the solute in this oddly-shaped vessel called a volumetric flask?
Why couldn't you just weigh out the solute into a beaker then add the required volume of water from a pipette?
Or, if the solute is a liquid or a solution, why not just pipette the required volume into a beaker then pipette the required volume of solvent into the same beaker?

So, why not try it?

Experiment (a) For solid solutes such as sodium chloride (table salt) or sucrose ("sugar") just pour the solid into a small DRY measuring cylinder until you have 5 mL for example. Pour this solid into a 100 mL measuring cylinder. Add 50 mL of water from a pipette (you will need to keep swirling the flask while you add the water). Record the volume of the final solution. Repeat the experiment using different volumes of solute and solvent.
Repeat this experiment using sand as the "solute" and water as the solvent.

Experiment (b)  For liquid solutes such as ethanol (ethyl alcohol) or acetone (propanone) use a pipette to place 50 mL of the solute into a 100 mL measuing cylinder then add 50 mL of water from a pipette and record the volume of the final solution. Repeat the experiment using different volumes of solute and solvent.
Repeat this experiment using vegetable oil as the "solute" and water as the solvent.

If a solute dissolves in a solvent, the volume of the final solution is not equal to the volume of the solute plus the volume of the solvent. Sometimes adding a solute to a solvent results in a solution with a volume less than that of the solvent + solute, and sometimes adding a solute to a solvent results in a solution with a volume greater than that of the solvent + solute. Right now, there are no good, general theories to explain this behaviour! But it is because of this that we use that oddly shaped piece of glassware called a volumetric flask when we make up a standard solution.

New Titration Resources

AUS-e-TUTE has just added new Complexometric Titration resources for the determination of calcium and magnesium ions in hard water.
Members can log-in to use the new tutorial, game, test and drill.

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