ABSTRACT : Nine gas-phase reactions that can be accomplished with an inexpensive, commercially-available glass-encased, heterogeneous palladium catalyst tube are described. The catalyzed reactions are suitable for demonstrating gas-phase reactions in the classroom or teaching laboratory. The reactions described include air or oxygen oxidations (CH4 + O2, CO + O2, NH3 + O2), hydrogenation of ethene, thermal decomposition of nitrous oxide, oxidations involving nitrogen dioxide (CH4 + NO2, CO + NO2), and two oxidation reactions involving nitrous oxide (N2O + NH3, N2O + CO). Several of the reactions demonstrate processes that take place in an automotive catalytic converter. In all cases, the products can be tested by simple chemical methods.