6-Exothermic reactions

• Acid and an alkali react to form a salt and water

  Hydrochloric acid + Sodium hydroxide --> Sodium chloride + water
• Glucose reacts with oxygen in the cells of organisms to release carbon dioxide. The energy released is used by the cells and tissues to stay alive and function properly.

  Glucose + Oxygen -> Carbon dioxide + Water
• The combustion of sulfur in oxygen produces sulfur dioxide gas.

  Sulfur + Oxygen —----------> Sulfur dioxide
• Sodium reacts rapidly and violently with water to produce sodium hydroxide and hydrogen gas. The reaction releases a lot of heat, causing the sodium metal and hydrogen gas to burn and give off light.

  Sodium + Water —> Sodium hydroxide + Hydrogen
• Magnesium reacts with dilute hydrochloric acid to produce magnesium chloride and hydrogen gas.

  Magnesium + Hydrochloric acid —--> Magnesium chloride + Hydrogen
• An exothermic reaction is a chemical reaction in which energy is

  given out to the surroundings.
• Energy is absorbed for breaking bonds, while energy is released for forming bonds. When the energy absorbed is less than the energy

  released, the reaction is exothermic.
• Neutralisation, aerobic respiration, combustion, reactions between alkali metals and water, and reactions between active metals and acids are some examples of exothermic reactions.