Exothermic vs Endothermic Reactions

Exothermic Reaction

Releases energy (usually as heat)
Feels hot to touch

Example:
CH₄ + O₂ → CO₂ + H₂O + heat
(Combustion of methane gas)

Fire, respiration, neutralization → all exothermic

Endothermic Reaction

Absorbs energy, usually heat
Feels cold to touch

Example:
CaCO₃ → CaO + CO₂
(Decomposition of limestone)

❄️ Photosynthesis is also an endothermic process (absorbs sunlight)