Understanding Candle Burning: Physical and Chemical Changes

The video discusses whether burning a candle is a physical or chemical change. It explains that burning a candle involves both physical and chemical changes. The melting and solidifying of wax is a physical and reversible change, while the burning of wax vapor, producing carbon dioxide and water vapor, is a chemical and irreversible change. Thus, candle burning is both a physical and chemical process.

What type of changes occur when a candle burns?

• Only physical changes

• Only chemical changes

• Both physical and chemical changes

• Neither physical nor chemical changes

What happens to the wax when a candle is lit?

• It melts and then solidifies upon cooling

• It turns into gas immediately

• It remains unchanged

• It evaporates completely

Which of the following is an example of a reversible change in candle burning?

• Wax melting and solidifying

• Emission of light

• Wax turning into vapors

• Production of carbon dioxide

What are the products formed when the wax vapors burn?

• Carbon dioxide and water vapor

• Sulfur dioxide and ash

• Nitrogen and methane

• Oxygen and hydrogen

Which type of change is associated with the production of heat and light in candle burning?

• Physical change

• Reversible change

• Chemical change

• No change