Q260: Prep Notes

Introduction

Two solutions are combined in a darkened room, producing luminescence that lasts for several seconds.

Peroxides act as an oxidizing agent.  The luminol is converted to an excited-state product.  This product decays to the ground state while emitting light.  Luminol is 3-aminophthalhydrazide.

Peroxide acts as an oxidizing agent.  The luminol is converted to an excited-state product.  This product decays to the ground state while emitting light. 

Supplies

Short List

  •   Tubing or spiral glass tube
  •   Funnel
  •   Two 250mL beakers
  •   600mL beaker
  •   Large crystallizing dish
  •   Goggles and gloves
  •   Paper towels

Chemicals

  •   Sodium carbonate
  •   Sodium bicarbonate
  •   Ammonium carbonate
  •   Cupric sulfate
  •   3-aminophthalhydrazide (luminol)
  •   30% hydrogen peroxide

Prior to Lecture  (prep time ~ ? min.)

  • Solution A: Dissolve 4.0g sodium carbonate in 800mL distilled water in a 1L flask.  Dissolve 0.2g luminol and add 24.0g sodium bicarbonate, 0.5g ammonium carbonate, and 0.4g cupric sulfate.  Stir until all solids are dissolved, dilute to 1L, and store in nalgene bottle.
  • Solution B: Dilute 5mL of 30% hydrogen peroxide to 1L with distilled water.  Date both solutions (they are stable for approximately one month).
  • Assemble the following: 
  •   Spiral delivery tube
  •   Two 250mL beakers
  •   600mL beaker

To Conduct Demonstration

  1. Position a beaker at the bottom of the spiral tube to collect the solution.
  2. Turn the lights down or off in the classroom.
  3. Pour equal amounts of solutions A and B simultaneously into the funnel at the top of the spiral tube.
  4. OPTIONAL: Activate variously colored light sticks.

Reaction Time: Leave for the rest of the class period

Safety and Disposal

Safety: Eye protection should be worn.

Disposal: dispose of chemicals in the luminol hazardous waste carboy.