Science Buddies: "Ask an Expert"

Hello! I am currently conducting an internal assessment for my DP Chemistry course. I am using this procedure as a baseline (https://www.sciencebuddies.org/science- ... -vitamin-c). However, at the end, instead of calculating the Vitamin C content via a standard solution, I am calculating it stoichoimetrically, using the formula of Ascorbic acid + I2 --> Dehydroascorbic acid + 2I- + 2H+.

In order to do so, I believe these are the steps:

Using the formula C = n/v
1. Find the concentration of the iodine (C).
2. Using the volume of mL of iodine that it took to reach the endpoint, convert to L, and substitute that for the variable (V).
3. Find moles of iodine.
4. Stoichiometrically go from mol iodine to mg of ascorbic acid.

I was wondering if this procedure looked correct to you? The main issue I'm facing here is the Lugol's iodine being a mixture of the I2 and the KI. I am also unable to find the concentration of the iodine in M (molarity), and was hoping you could help with this too. This counts as a huge portion of my exam grade which is why I am hoping you can give me some help. Thank you so much!

Hello.

This forum is meant to help students with their science fair projects. There are other websites more suited to help with homework / test questions.

Thanks, and good luck!

dcnick96 wrote:Hello.

This forum is meant to help students with their science fair projects. There are other websites more suited to help with homework / test questions.

Thanks, and good luck!

Hello, this is a science fair question. I'm not sure if you looked at my post but I mentioned that I am using a science buddies procedure for the project, but adapting the very end of it in terms of calculations in order to bring it to a more advanced level. I would appreciate if you could reread that, as it is related to a science fair project, but a question on an alternative way to calculate the Vitamin C concentration as opposed to what is outlined on the science buddies procedure.

Hi - I think the confusion may be caused by the fact that you titled your post "exam question" and also mentioned in your post that this is a large portion of your "exam" grade.

Have you tested the procedure that you've outlined?

I understand you used the Science Buddies procedure as a starting point. What is the hypothesis for the project you are now doing?

Amy