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Combustion of Hydrogen

Procedure

Balloons filled with hydrogen gas are tethered to a weight with a string and lit with a match taped to a yardstick.

Usually done with:

• 1 Balloon filled with Hydrogen (big bang)
• 1 Balloon with mixed Hydrogen and Oxygen (bigger bang)

Reactions:

2H₂ (g) + O₂ --> 2H₂O (g)

The Change in Enthalpy (delta H)
dH = -232 kJ/mole

Note on Safety: Both balloons in this demo should be behind the large plex shield (to protect the audience from small pieces of balloon) and the the balloons should be sized (about 4 inches in diameter is what I use for the fuel/oxygen balloon) so that the bang is not loud enough to cause ringing in the ears.
When I do this type of demonstration I also warn the audience to cover their ears for the "loud" explosion and light off the balloon on the count of 3... [and I do it at the end of the period because it brings down lots of chalk dust which can irritate eyes & lungs].
NOTE: the person doing the demonstration should be wearing safety goggles and hearing protection. They should also choose their clothing (no synthetics or flammables) carefully to insure they don't become part of the demo.