Endothermic

Key Stage 3

An endothermic process is one takes in energy. This usually causes surroundings to decrease in temperature.

A few chemical reactions are endothermic with means they need energy from the environment and this is observed by a decrease in temperature.


The energy stored in the reactants less than the energy stored in the products. This means the reaction must take in energy from the environment which causes the surroundings to decrease in temperature.

Melting, Evaporating and Subliming are endothermic changes because they need energy to happen. The material has more energy at the end than it did the beginning. However, there is usually no decrease in temperature because the material is usually being heated to change state.

Dissolving is an endothermic process as energy is needed to break the bonds in the solid solute to dissolve. This causes the solution to decrease in temperature while the solute is dissolving.

An endothermic process is one takes in energy. This usually causes surroundings to decrease in temperature.

Endothermic reactions usually require energy to begin. This is called the activation energy.

In an endothermic process the potential energy stored in the reactants is less than the potential energy stored in the products.


To start the reaction an activation energy is needed. This is usually achieved by initially heating the reactants. Once the reaction starts, since the energy stored in the reactants less than the energy stored in the products, this means the reaction must take in energy from the environment which causes the surroundings to decrease in temperature.

In a chemical reaction energy is needed to break the chemical bonds holding the atoms together.

In an endothermic reaction more energy is taken in breaking the bonds in the reactants than is released in the formation of new bonds in the products. So there is a net input of energy.