Question

A person eats chocolate and digests it. In doing so here takes place a physical and chemical change, identify the changes and give a reason for your answer.

Answer 1

• Eating of chocolate involves chewing, such that it melts in the mouth. During the chewing process, only state changes.
• Therefore, it is a physical change.
• During the digestion of chocolate, the material in it ultimately breaks down in cells producing carbon dioxide and water along with the release of energy.
• Hence digestion is a chemical change.

Chemical change:

• A chemical change is a permanent change in which new substances are formed.
• The chemical change is permanent and cannot be reversed by a simple physical method.
• A chemical change involves an exchange of energy in the form of heat or light.
• For example, rusting of iron, burning of wood, respiration, etc.

Physical change:

• A physical change is a change in which no new substance is formed.
• A physical change is temporary and reversible.
• In physical change the chemical composition of the original substance is not altered.
• For example, drying of wet clothes, breaking of a glass tumbler, drying paints, etc.