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Low-boiling alcohols vaporize readily, and when alcohol is placed in a 5-gallon, small-mouthed jug, it forms a volatile
mixture with the air. A simple match held by the mouth of the jug provides the activation energy needed for the
combustion of the alcohol/air mixture.
Only a small amount of alcohol is used and it quickly vaporizes to a heavier-than-air vapor. The alcohol vapor and air are
all that remain in the bottle. Alcohol molecules in the vapor phase are farther apart than in the liquid phase and present far
more surface area for reaction; therefore the combustion reaction that occurs is very fast.
Since the burning is so rapid and occurs in the confined space of a 5-gallon jug with a small neck, the sound produced is
very interesting, sounding like a “whoosh.” The equation for the combustion reaction of isopropyl alcohol is as follows,
where 1 mole of isopropyl alcohol combines with 4.5 moles of oxygen to produce 3 moles of carbon dioxide and 4 moles of
water:

(CH3)
2CHOH(g) + 9⁄2O2(g) → 3CO2(g) + 4H2O(g) ∆H = –1886.6 kJ/mol

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