'∆H' will be given a negative sign in:
Correct answer: A. Exothermic reactions
- A. Exothermic reactions
- B. Decomposition reactions
- C. Dissociation reaction
- D. Endothermic reactions
Explanation
In exothermic reactions, heat is released to the surroundings as a product. This means that the enthalpy change (∆H) is negative because the system loses energy in the form of heat. The negative sign indicates that the reaction releases heat and is exothermic.In contrast, endothermic reactions absorb heat from the surroundings, which means that the enthalpy change (∆H) is positive. Decomposition and dissociation reactions can be either endothermic or exothermic, depending on the specific reaction and the energy involved.
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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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