E

Endothermicity

ΔH > 0; q_p > 0 (heat absorbed)
Quick Reference
Formula / NotationΔH > 0; q_p > 0 (heat absorbed)
Also Known AsEndothermic character; heat absorption; positive enthalpy change; ΔH > 0; endothermal

What is Endothermicity?

Endothermicity refers to the property of a reaction or process that absorbs heat from the surroundings. An endothermic reaction has a positive enthalpy change (ΔH > 0), meaning the products have higher energy than the reactants. The surroundings cool down as heat flows into the system. Endothermicity is the opposite of exothermicity.

Formula & Notation

ΔH > 0; q_p > 0 (heat absorbed)

Other Names / Synonyms: Endothermic character; heat absorption; positive enthalpy change; ΔH > 0; endothermal

Properties & Characteristics

ΔH > 0 (positive); heat absorbed from surroundings; surroundings cool; products at higher energy than reactants; examples: photosynthesis, melting of ice, decomposition of CaCO₃; may be non-spontaneous unless TΔS overcomes ΔH (when ΔG = ΔH − TΔS < 0)

Uses & Applications

Cold packs (endothermic dissolution of NH₄NO₃); refrigeration cycles; photosynthesis; thermal decomposition reactions in industry; endothermic metal extraction processes; modelling reaction energetics

Safety Information

No direct hazard from the concept. Some endothermic reactions require high temperatures or explosive conditions to initiate. Cold packs (NH₄NO₃) are safe but the salt is an oxidiser/explosive hazard in concentrated form.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Endothermicity
Formula ΔH > 0; q_p > 0 (heat absorbed)
Synonyms Endothermic character; heat absorption; positive enthalpy change; ΔH > 0; endothermal

Frequently Asked Questions

Endothermicity refers to the property of a reaction or process that absorbs heat from the surroundings. An endothermic reaction has a positive enthalpy change (ΔH > 0), meaning the products have higher energy than the reactants. The surroundings cool down as heat flows into the system. Endothermicity is the opposite of exothermicity.

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