Exothermic Reactions in Chemistry

Study Notes

Exothermic reactions transfer energy from the reacting molecules to the surroundings, causing the temperature of the surroundings to increase.
Examples of exothermic reactions include combustion (burning), certain oxidation reactions, and neutralization.
Energy profile diagrams of exothermic reactions show that the products have less energy than the reactants, indicating that energy has been released to the surroundings.
The difference between the energy of the reactants and the energy of the products represents the energy released to the surroundings.
Exothermic reactions have practical applications, such as in hand-warmers and self-heating cans containing food or drink.

Endothermic reactions take in energy from their surroundings, causing the temperature of the surroundings to decrease.
Thermal decomposition is an example of an endothermic reaction.
Energy profile diagrams of endothermic reactions show that the products have more energy than the reactants, indicating that energy has been taken in from the surroundings.
The difference between the energy of the reactants and the energy of the products represents the energy taken in by the reaction.

The activation energy is the minimum amount of energy that particles must have to react with each other.
Reactions can only occur when particles collide with sufficient energy.
The activation energy is represented on energy profile diagrams as the energy from the reactants to the peak of the curve.
It is a key concept in understanding exothermic and endothermic reactions.

Exothermic reactions release energy from reacting molecules to surroundings, increasing the temperature of the surroundings.
Examples of exothermic reactions include combustion, certain oxidation reactions, and neutralization reactions.
Energy profile diagrams show that products have less energy than reactants, indicating energy release to surroundings.
The energy difference between reactants and products represents the energy released to surroundings.

Endothermic reactions absorb energy from surroundings, decreasing the temperature of the surroundings.
Thermal decomposition is an example of an endothermic reaction.
Energy profile diagrams show that products have more energy than reactants, indicating energy absorption from surroundings.
The energy difference between reactants and products represents the energy taken in by the reaction.

Activation energy is the minimum energy required for particles to react with each other.
Reactions occur when particles collide with sufficient energy.
Activation energy is represented on energy profile diagrams as the energy from reactants to the peak of the curve.
It is a crucial concept in understanding exothermic and endothermic reactions.