Oxygen thermochemical water/carbon dioxide

Self-Tfst 6.11B When 0.338 g of pentane, C5H12, burns in an excess of oxygen to form carbon dioxide and liquid water in the same calorimeter as that used in Self-Test 6.1 1A, the temperature rises by 76.7°C. Write the thermochemical equation for the reaction. 

A thermochemical analysis indicates that water and carbon dioxide are more stable than ethane and oxygen. Presumably, this is the reason ethane explodes when the match is lit. Energy is all too obviously given off as heat and light. But why do objects that are stable in air, such as ethane or wood, explode or burn continuously when ignited How are they protected imtU the match is lit ... 

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