To overcome an energy barrier between reactants and products in a chemical reaction, energy must be provided to get the reaction started. this energy, which is recovered as the reaction proceeds, is called:

a 20-cm-long, cylindrical graphite (pure carbon) rod is inserted into an oxidizing atmosphere at 1145 k and 1.013 x 105 pa pressure. the oxidizing process is limited by the diffu- sion of oxygen counterflow to the carbon monoxide that is formed on the cylindrical surface.

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