What does one mean by exothermic and endothermic reactions? Give examples.
Exothermic reaction: A reaction in which energy is released in the form of heat or light.
Eg.: Burning of Natural gas (methane)
CH4(g) + O2(g) → CO2(g) + H2O(l) + Heat
Endothermic reaction: A reaction in which energy is absorbed from the surroundings and cooling is produced.
Eg.: Decomposition of calcium carbonate
CaCO3(s) -------------→ CaO(s) + CO2(g)
Calcium Carbonate Calcium oxide Carbon dioxide
or Lime stone or quick lime
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