Which of the following represents a chemical change?
Melting of ice
Burning of wood
Breaking of glass
Evaporation of water
Burning of wood
A chemical change involves a reaction that results in the formation of new substances with different chemical properties. Let's analyze each of the given options to determine if it represents a chemical change:
1. Melting of ice: Melting is a physical change where solid ice turns into liquid water. There is no change in the chemical composition of water molecules, so this is not a chemical change.
2. Burning of wood: Burning is a chemical change known as combustion. When wood is burned, the chemical compounds in the wood undergo a reaction with oxygen from the air, resulting in the production of carbon dioxide, water vapor, and ash. Therefore, the burning of wood represents a chemical change.
3. Breaking of glass: Breaking of glass is a physical change. It involves the separation of glass into smaller pieces, but there is no change in the chemical composition of glass. Hence, this is not a chemical change.
4. Evaporation of water: Evaporation is a physical change where liquid water turns into water vapor. When water is heated, its molecules gain enough energy to overcome intermolecular forces and escape as vapor. The chemical composition of water remains the same during evaporation, making it a physical change.
Therefore, among the given options, the burning of wood represents a chemical change.