Is ΔH positive or negative for exothermic reactions?

For exothermic reactions, ΔH is negative because energy is released, so the products have lower enthalpy than the reactants.

Is melting of ice endothermic or exothermic?

Melting of ice is endothermic — it absorbs heat from the surroundings to break the bonds holding the solid structure together.

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Difference Between Endothermic Reaction and Exothermic Reaction

Chemical reactions either absorb or release energy as heat. This decides whether they are endothermic or exothermic.

In short

Endothermic reactions absorb heat from the surroundings (ΔH is positive, surroundings cool); exothermic reactions release heat to the surroundings (ΔH is negative, surroundings warm).

Endothermic Reaction vs Exothermic Reaction — Comparison Table

Basis	Endothermic Reaction	Exothermic Reaction
Heat	Absorbed	Released
Enthalpy change (ΔH)	Positive (+)	Negative (−)
Surroundings	Get colder	Get warmer
Energy of products	Higher than reactants	Lower than reactants
Examples	Photosynthesis, melting ice	Combustion, respiration

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Frequently Asked Questions — Endothermic Reaction vs Exothermic Reaction

Is ΔH positive or negative for exothermic reactions?: For exothermic reactions, ΔH is negative because energy is released, so the products have lower enthalpy than the reactants.
Is melting of ice endothermic or exothermic?: Melting of ice is endothermic — it absorbs heat from the surroundings to break the bonds holding the solid structure together.

Difference Between Endothermic Reaction and Exothermic Reaction

Endothermic Reaction vs Exothermic Reaction — Comparison Table

Frequently Asked Questions — Endothermic Reaction vs Exothermic Reaction

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