Examples of Exothermic Reactions

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Last updated on September 30th, 2019 at 03:28 pm

Exothermic reactions are those chemical reactions that release heat energy during the process. One of the most common examples of an exothermic reaction is the rusting of iron. The measurement of absolute energy corresponding to such reaction is difficult. However, the change in enthalpy, a thermodynamic state function, can be measured easily.

Please note that the enthalpy change of a chemical reaction is the total of the change in internal energy and the work done against constant pressure. We can also define an exothermic reaction as a reaction where the change of enthalpy is negative.

Below we mention 10 examples of exothermic reactions.

10 Examples of Exothermic Reactions with Equations

  1. Combustion Reaction: Combustion is a reaction where a fuel (like methene, glucose, petroleum, etc. ) undergoes reduction when exposed to an oxidizing agent under certain circumstances. A popular example of combustion reaction is burning of glucose C_6H_{12}O_6+6O_2 \rightarrow 6CO_2+6H_2O+Energy. This is the reaction happening in our body and the energy released is driving us. Similar Post: Examples of Chemical Energy.
  2. Reaction of Sodium with Water: Sodium reacts rapidly with water and forms the solution of Sodium Hydroxide (NaOH). The reaction is exothermic in nature. 2Na + 2H_2O \rightarrow 2NaOH + H_2+Energy
  3. Rusting of iron: Rusting or corrosion of iron is an exothermic reaction. Though the rate of reaction is very slow, a finite amount of energy is released during the process. 4Fe + 3O_2 + 6H_2O \rightarrow 4Fe(OH)_3+Energy
  4. Burning of Match Sticks: The tip of a match stick contains Potassium Chlorate (KClO_3), Sulfur (S), Starch, Glue, and other compounds. The surface of the box contains glass powders, red Phosphorus, and glue. The friction produces enough heat to cross the activation barrier and results in the burning of the stick. 16KCl_3 + 3P_4S_3 \rightarrow 16KCl + 9SO_2+Energy
  5. Burning of Hydrogen: Burning of Hydrogen is another example of exothermic reaction. The end product is water and heat. 2H_2 + O_2 \rightarrow 2H_2O+Energy. Good to Know: 10 Examples of Potential Energy.
  6. Nuclear Fission of Uranium-235: In this fission reaction one atom of U-235 releases 202.5 MeV energy. n^0_1+U^{235}_{92} \rightarrow Ba^{141}_{56}+Kr^{92}_{36}+3n^1_0+Energy
  7. Reaction of Magnesium with Oxygen: The reaction of Mg metal with O2 produces Magnesium Oxide and releases energy. 2Mg+O_2 \rightarrow 2MgO + Energy
  8. Decomposition of KClO3: Decomposition of Potassium Chlorate produces Potassium Chloride (KCl) and gaseous Oxygen. This is also another example of exothermic reaction.
  9. Dehydrating Sugar with Sulfuric Acid: Concentrated sulphuric acid is a strong dehydrating agent. Reaction of H2SO4 with Sugar is a type of exothermic elimination reaction. C_{12}H_{22}O_{11}+H_2SO_4 \rightarrow 12C+ 11H_2O + H_2SO_4+ Energy
  10. Thermite Reaction: In thermite reaction, Iron Oxide reacts with Aluminium to produce molten Iron and heat energy. Fe_2O_3 + 2Al \rightarrow 2Fe + Al_2O_3 + Energy