Question

Difference between thermal reaction and photochemical reaction

Answer 1

Thermal Energy.

In thermal energy the energy of activation is gained by the collision of molecules.

The rate of reaction depends on the temperature.

It is accompanied by the decrease in the energy.

Inter molecular collision results in the excitation of the molecules.

Photochemical energy

Rate of reaction is independent of temperature and it depends on the intensity of the radiation.

Free energy of photochemical reaction may increase as some of the radiation energy will get converted into chemical energy.

A single molecule can be promoted to excited state.

Answer 2

The major difference between thermal reaction and photochemical reaction:      

• Thermal reactions occur in the presence of heat whereas photochemical reactions occur in the presence of light.
• Thermal reactions involve absorption of heat whereas in the photochemical reaction it involves absorption of the photon.
• These two reactions are comes under in chemical reaction.
• A chemical reaction involves the conversion of some molecules to form a new molecule. Here the initial molecules are called reactants whereas the newly formed molecules are called products.
• On the basis of bond breaking and reactions conditions, they can be classified in different types like thermal reaction, photochemical reactions.