Which of the following processes has always ΔH=-ve?
Correct answer: B. Combustion
- A. Formation of compound
- B. Combustion
- C. Dissolution of ionic compound
- D. Dilution of a solution
Explanation
Combustion is defined as a rapid reaction with an oxidant, usually oxygen, to produce heat and light. By its very nature, it is an exothermic process, meaning it always releases energy and has a negative enthalpy change (ΔH < 0).
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About Thermochemistry and Energetics of Chemical Reactions
Thermochemistry measures energy changes in chemical reactions and distinguishes exothermic from endothermic processes. Work covers systems, surroundings and state functions, internal energy, the first law of thermodynamics, enthalpy and Hess's law, including the sign conventions used when heat enters or leaves a system.
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