Question

How does energy play a role in chemical reactions and describe its role in a chemical reaction that you have seen or done in your everyday life.(endothermic and exothermic reactions)

Answer 1

• All chemical reactions involve energy. Energy is used to break bonds in reactants, and energy is released when new bonds form in products. Like the combustion reaction in a furnace, some require less energy to break bonds in reactants than is released when bonds form in products. These reactions, called exothermic reactions, release energy. In other chemical reactions, it takes more energy to break bonds in reactants than is released when bonds form in products. These reactions, called endothermic reactions, absorb energy.

A reaction in which energy is released to the surroundings is called an exothermic reaction. In this type of reaction the enthalpy, or stored chemical energy, is lower for the products than the reactants.

• Role in everyday life:

The chemical reaction by which plants produce complex food molecules (sugars) requires an energy input (i.e., from sunlight) to occur. Both the burning of fuel and cellular digestion in plants and animals involve chemical reactions with oxygen that release stored energy.