Final answer:
In a combustion reaction with pure oxygen, a compound combines with the oxygen to form oxides, releases energy as heat, and is typically highly exothermic.
Step-by-step explanation:
When a compound undergoes combustion in the presence of pure oxygen, it reacts with the oxygen to produce oxides and releases energy in the form of heat and often light. This type of reaction, known as a combustion reaction, is exothermic and can be highly vigorous. For instance, the combustion of methane (CH4) in the presence of oxygen (O2) results in carbon dioxide (CO2) and water (H2O), alongside a significant release of heat:
CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O(g) + Heat
These reactions are also redox processes where the fuel is oxidized, and the oxygen is reduced. Oxygen plays a crucial role in supporting combustion, and in a pure oxygen environment, the reaction rate can increase significantly, resulting in a more intense combustion compared to that in air.