Science Buddies: "Ask an Expert"

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

Hi

Im working on this for the science fair project
However, i have some huge questions about this
1. Is the 5-aminophthalic acid and 3-aminophthalic acid same?
Because only here (https://www.sciencebuddies.org/science- ... background) mention 5-aminophthalic acid, whereas other site are talking about 3-aminophthalic acid
2. Could you tell me what is the chemical formula for this experiment?
3. Why do you need dim light for this?

Thank you

Hi Hahmmyeongjo,

Sometimes chemical names can get confusing! But I think that 5-aminophthalic acid is the same as 3-aminophthalic acid. I believe that the more commonly used name is 3-aminophthalic acid.

I’m not sure what you mean by the chemical formula for the experiment. The reaction involved is shown and explained in the background section of the project. In brief, luminol reacts with hydroxyl ions (OH-) and oxygen to form 5-aminophthalic acid and nitrogen gas. The chemical formula for luminol is C8H7N3O2.

You want to dim the lights to better see the glow produced by the luminol reacttion.

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

A. Norman

Thank you!
What i meant about the chemistry formula was about the chemistry equation.
Could you tell me what is the chemistry equation for this experiment, please?

Hi Hahmmyeongjo,

I think that the net reaction described in the project background can be written as:

C8H7N3O2 + 2NaOH + 2H2O2 ---> Na2C8H5NO4 + N2 + 4H2O

But this way of writing the reaction isn’t as informative as the mechanism outlined in the background section of the project description. That’s the reason that many reactions involving complex chemicals or multiple reaction steps are described this way instead of with a chemical equation.

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

A. Norman