Science Buddies: "Ask an Expert"

Hello,

We are doing a science experiment that requires Titration. The exact experiment is Which cooking method is the least damaging on vitamin c levels in peppers. What materials would we need for titration and what the procedure for titration. We are in Canada, Newfoundland SO we do not have access to the same stores as you do, but where would we get the necessary materials, not including thing like beakers ect....

Thanks you

Take a look at the methods section of this project:

https://www.sciencebuddies.org/science- ... PAodNAUAHw

You can get materials on line at Amazon, or

http://www.scientificsonline.com/

or

http://www.stevespanglerscience.com/cat ... b-supplies

Hope this helps. Good luck!

Hi Cleocurls,

John has given you some helpful advice on finding the materials you will need for this project. I think you are doing this really excellent project from the Science Buddies website:

https://www.sciencebuddies.org/science- ... ml#summary

There is a detailed list of materials in the procedure that John referred you to and there is also a kit available that will save a lot of time in tracking down materials. You will have to inquire about shipping to Newfoundland.

https://store.sciencebuddies.org/Chem_p ... e-Kit.aspx

Please post again in this topic if you have any more questions.

Good luck!

Donna Hardy

Hi I was wondering if I were to do an experiment on the effect of different cooking methods on the the depletion of Vitamin C in peppers whether it mattered if I used Soluble starch and Lugol's iodine solution or if I used instead Potassium Iodate and Potassium iodide with soluble starch.

Hi Cleo,

Good question. Unfortunately, potassium iodate is in the wrong oxidation state for this reaction, so you do need iodine and potassium iodide. It's actually the elemental iodine that interacts with the starch molecules to give the dark blue color.

Donna

Okay... I know that you already have the procedure/materials up on your site but me and my partner am very confused on how to titrate and on what we need to titrate. For example here: http://www.outreach.canterbury.ac.nz/ch ... iodate.pdf we are reading different things. COuld you simplify the whole thing... because this does not make sense to us.....Thanks

Titration is a process that requires some kind of an indicator and a know concentration of a reagent solution. In your experiment, the indicator is a change of color. So after adding your indicator to your test solution, you are going to slowly add very small amounts of your reagent while stirring your solution under test until you observe the color change. The amount of reagent solution times its known concentration will tell you how much of the reagent you had to add to balance your unknown solution.

Hope this helps. Without knowing your exact proceedure, I can't be more specific.

Hi Cleo,

Craig has given you excellent information for doing a titration. Here are some more tips:

The specific procedure you will be following on this project is included on a link inside a link in the background information for the project guide:

http://www.outreach.canterbury.ac.nz/ch ... iodine.pdf

You will have the iodine solution in a calibrated burette and add it drop by drop to the sample containing vitamin C until you see the stable blue-black color end point. Do read the entire link before you start as it includes lots of helpful details.

Donna Hardy