Practical investigations
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I am currently doing an experimental investigation on wine making. We have done back titrations and we have tested the sulphur dioxide content in our wine. Our group is stuck on figuring out the calculations to finding out the sulphur dioxide content.
Igloo writes ...
It’s difficult to give you too much help since you do not mention the technique you have used, and in any case I obviously cannot do your work for you, given that this is an internally assessed part of your exam!
On the assumption that you have carried out titrations with iodine solution (with the standard iodine solution in the burette), the steps would be:
1 From your titration reading and the known concentration of the iodine, work out the number of moles of iodine used.
2 Use the equation between iodine and sulphur dioxide to deduce the number of moles of sulphur dioxide in your wine sample.
3 Knowing the volume of wine pipetted into the flask, scale up the number of moles to what would be found in 1 dm3. You now have the concentration in mol dm-3.
4 If necessary, convert this to p.p.m. (parts per million) or mg per dm3, via the molar mass of SO2.
If this wasn’t the technique you used please re-submit your question via React and let us know a little more detail about the procedure.
Always carry out a risk assessment and check with your teacher before starting any practical work.
Risk assessment
Before attempting any practical work based on the advice and suggestions on this website, you must do the following. Identify any hazards, assess the risks from these hazards, and then decide appropriate control measures to reduce the risks. You must have these approved by those in authority in your school or college laboratory. Do not rely on what is said on this website.
For further guidance see our tutorial on Risk Assessment.
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updated: 17 December 2006
