University of Virginia
Physics Department

## Chemiluminescence: The Blue Glow

A Physical Science Activity

### Student Activity

Materials

• Liquid chlorine bleach, 25 mL
• Distilled water, about 500 mL
• Luminol, 0.12 grams
• Ice bath
• Balance
• Thermometer
• Funnel (optional)
• Clear plastic tubing (optional)

WARNING: Bleach is very reactive. It will combine and change in chemical reactions very quickly and with lots of energy. This also makes it very dangerous.

Procedure

1. Use a balance to measure 0.12 lgrams of luminol. First, find the mass of a piece of paper. Place the luminol on the paper and measure the mass again. Find the difference of the masses until you have the proper amount of luminol.  *
2. Make the luminol solution by dissolving 0.12 grams of luminol in 250 mL of distilled water.
3. Make the bleach solution by mixing 25 mL of liquid chlorine bleach with 225 mL of distilled water.
4. Place the solutions in an ice bath, but do not let them freeze.
5. Measure the temperature of each of the solution.
6. Darken the room.
7. Use a funnel connected to a plastic tube and pour the contents of both beakers into the funnel at the same time. The tubing will empty into another beaker. **
8. Measure the temperature of the mixture.

*If available, electronic balances would allow more precision.

**If the funnel and plastic tube are not being used, then simply pour the contents of both the luminol and bleach solutions into another beaker at the same time.

Data Sheet

Temperature of luminol solution___________________

Temperature of bleach solution___________________

Final temperature of mixture_____________________

1. Describe the solution that was made when you mixed the luminol with the distilled water.

2. Describe the liquid chlorine bleach solution.

3. What happened when you mixed the two solutions together?

4. Describe the evidence that a chemical reaction occurred.

5. Was there any difference in temperature before and after the luminol and bleach solution were mixed together?

6. Was this an endothermic or exothermic reaction? How do you know?

7. How might chemiluminescence be useful to living organisms such as fireflies?

8. Name some practical uses of chemiluminescence by humans.