An exciting, and often loud, chemical demonstration involves the simple reaction of hydrogen gas and oxygen gas to produce water vapor:
2H2(g) + O2(g) → 2H2O(g)
The reaction is carried out in soap bubbles or balloons that are filled with the reactant gases. We get the reaction to proceed by igniting the bubbles or balloons. The more H2O that is formed during the reaction, the bigger the bang. Explain the following observations.
a. A bubble containing just H2 makes a quiet “fffft” sound when ignited.
b. When a bubble containing equal amounts of H2 and O2 is ignited, a sizable bang results.
c. When a bubble containing a ratio of 2 to 1 in the amounts of H2 and O2 is ignited, the loudest bang results.
d. When a bubble containing just O2 is ignited, virtually no sound is made.