Why is a combustion reaction generally exothermic?
Answer and explanation
Correct answer: More energy is released when product bonds form than is absorbed to break reactant bonds.
In combustion, a fuel reacts with oxygen to form new products such as carbon dioxide and water. Energy is required to break bonds in the reactants, but more energy is released when new, more stable bonds form in the products. Therefore, heat is released overall, making combustion exothermic. Option B describes the opposite energy balance, which would correspond to an endothermic reaction.
Frequently asked questions
What is the correct answer to this question?
More energy is released when product bonds form than is absorbed to break reactant bonds.
Why is this the correct answer?
In combustion, a fuel reacts with oxygen to form new products such as carbon dioxide and water. Energy is required to break bonds in the reactants, but more energy is released when new, more stable bonds form in the products. Therefore, heat is released overall, making combustion exothermic. Option B describes the opposite energy balance, which would correspond to an endothermic reaction.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Chemical Reactions and Equations.
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