Science Buddies: "Ask an Expert"

Hello,

I need help with this:
I am completing an experiment to determine the amount of vitamin c content in orange juice at different temperatures. I have done the titration and am now doing the calculations. I used 20 mL of orange juice and added 150 mL of distilled water. I am using the M1V1=M2V2 formula to determine the concentration of ascorbic acid in the orange juice. Do I use 20 mL as my known volume for orange juice? I was confused because the water and orange juice were titrated together.


Thank you,
Mary

Hi Mary,

I'm assuming that your titration is similar to the one described in this project:

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

With this method you use the volumes of iodine indicator needed to titrate a standard vitamin C solution along with the volume to titrate orange juice. The calculations use equations 1, 2 and 3 in the project procedure. Equation 3 gives the mass of vitamin C in the orange juice. If you want the concentration of vitamin C in the juice, divide the mass as calculated from equation 3 by the 20 mL juice volume you used.

I hope this helps. Please ask again if you have more questions.

A. Norman