Science Buddies: "Ask an Expert"

Hi,
I am doing my project on how temperature affects luminal glow. I am having trouble understand just exactly WHY it affects it. I understand how it reacts to blood and things like that but I just can't find anything to explain why the temperature of water would affect it. I am in 9th grade so I haven't taken Chemistry yet. Any help or explanations would be extremely helpful.

Thanks in advance,
Afulfillinglife

Hello afullfillinglife,

I’m assuming that you’re working on the project described here:

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

In chemical reactions the starting materials form different materials called reaction products. How fast the reaction products form is of great interest. Reaction kinetics is an area of chemistry devoted to the study of reaction rates. For most reactions, the rate (or how fast the reaction proceeds to the products) depends on the temperature. This is because molecules need a certain amount of kinetic energy to react. Increasing the temperature increases the number of molecules with enough kinetic energy so the rate of reaction will increase. More information on this topic is available here:

http://chemwiki.ucdavis.edu/Core/Physic ... emperature

In your project, light is emitted when luminol reacts as outlined in the project background section. The light is a reaction product. When you increase the temperature, more of the luminol molecules have enough energy to emit light. And the reaction rate should be faster.

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

A. Norman

Hi A. Norman,

Thank you SOOO much. I definitely understand it much better now!!

Thanks,
Afulfillinglife

Hi again,

So I did the experiment and after they stopped glowing they turned different colors. The hot water one turned a very light blue, the cold water one turned a yellow and the room temperature one turned green. Do you know why it did that?
Also is there a special way to dispose of the liquid or can I just pour it down the sink?

Thank you so much,
Afulfillinglife

Hi afullfillinglife,

Thanks for asking about disposal of your luminol solutions. Chemistry experiments should include plans for safe handling and disposal of the chemicals. After checking a couple of sources I think it’s OK to flush your luminol solutions down the drain. You may be interested in the information about luminol at the following links.

http://chemwiki.ucdavis.edu/Under_Const ... ns/Luminol

http://www.flinnsci.com/Documents/demoP ... F10237.pdf

I don’t know why “after-reaction” solution color varied with temperature. Perhaps another forum contributor will have some ideas on this.

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

A. Norman

Thanks so much for all the answers I think I understand it all now! It really helped with writing my science fair paper!

Afulfillinglife

Hi A. Norman,

I know this is a little late but I just wanted to thank you!! I won first place in my science fair and you helped a TON!!

Thank you so very much!!

Hi afullfillinglife,

Congratulations on your science fair project!
You’re welcome – glad to help.

A. Norman