Exothermic and Endothermic reactions

What are exothermic reactions

Reactions that transfer energy from the reacting molecules to the surroundings

What happens to the surroundings in exothermic reactions

Get hotter

Examples of exothermic reactions

Combustion

Neutralisation

Certain oxidation reactions

How do scientists represent the energy changes that take place in reactions

Draw energy profile diagrams

Exothermic energy profile diagram

Reactants start high and go down to products

Why do the products in exothermic reactions have less energy than the reactants

Because energy had been lost and transferred from the reaction to the surroundings

How to figure out how much energy has been lost to the surroundings in energy profile diagrams

Difference between reactants down to products

Uses of exothermic reactions

Hand warmers

Self heating cans for food and drink

What are exothermic reactions

Reactions that take in energy from the surroundings

Examples of endothermic reactions

Thermal decomposition

Photosynthesis

What happens to the surroundings of endothermic reactions

They get colder

Energy profile diagram of an endothermic reaction

Reactants go up to products

Why do the products have more energy than the reactants in endothermic reactions

Because energy has been gained and taken in from the surroundings

When do reactions occur

When the particles collide with each other with sufficient energy

What is the activation energy

The minimum amount of energy that particles just have in order to react

Where is the activation energy on an energy profile diagram

From the reactants to the peak of the curve