Exothermic Reactions

Exothermic Reaction

  1. Exothermic reaction is the chemical reaction that releases heat to the surrounding.
  2. When energy is given off during a chemical reaction, the temperature of the surrounding will increase.

Example of Exothermic Reaction

Reaction Equation

Diluted sulphuric acid is neutralized by sodium hydroxide aqueous

H2SO4 + 2NaOH → Na2SO4 + 2H2O
Acid + carbonate

Reaction between hydrochloric acid and sodium carbonate

2HCl + Na2CO3 → 2NaCl + CO2 + H2O
Calcium oxide + water
CaO + H2O → Ca(OH)2
Water + dehydrated copper(II) sulphate
CuSO4 + xH2O → CuSO4xH2O
Dissolve NaOH and KOH in water
NaOH + water → Na+ + OH
KOH + water → K+ + OH
Reaction between alkali metal (Li/Na/K) and water

Sodium + Water

2Na + 2H2O → 2NaOH + H2
Reaction between reactive metal (Mg/Al/Zn/Fe) and diluted acid

Magnesium + Nitric acid

Mg + 2HNO3 → Mg(NO3)2 + H2

Combustion of methane

CH4 + 2O2 → CO2 + 2H2O


  • Rusting
  • Dilution of concentrated sulphuric acid/ concentrated nitric acid or others acid in water.
  • Crystallization of sodium tiosulphate.
  • Change of state from gaseous state to liquid state and liquid state to solid state.

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