Light Producing Chemical Reactions

Matthew Landry CHEM 1202 – General Chemistry II

Spring Intersession 2012

What is Light?

•  The natural agent that stimulates sight and makes things visible

•  Electromagnetic radiation from about 390

to 740 nm in wavelength.

Part I: Chemiluminescence

• Certain organic chemical reactions can produce light either by luminescence or phosphorescence.

•  Firefly • Chemical reactions that release energy that is efficiently converted to light, but almost no heat.

Part II: Quantum Fireballs

•  Lithium (Li) •  Sodium (Na) •  Potassium (K) •  Calcium (Ca) •  Strontium (Sr) •  Copper (Cu)

• Fireworks and Pyrotechnics

Part II: Quantum Fireballs

• General Reaction M+n ion + Heat Energy à {M+n excited state} à M+n + Light Emitted

Part II: Quantum Fireballs

Each metal has its own light emission profile, due to the differences of electron orbital energies unique to that element.

Part III: Burning Mg in CO2

• Fire extinguishers • The heat produced by this reaction

which begins in the open atmosphere is sufficient to decompose the CO2.

Mg(s) + CO2 à MgO (s) + C(s)