Understanding Candle Combustion

The video explains how a candle can be relit without the flame touching the wick due to the flammable wax vapor. It covers the composition of candles, focusing on paraffin wax and hydrocarbons. The combustion process is detailed, showing how the wick absorbs melted wax, which vaporizes and reacts with oxygen to produce heat and light. Experiments demonstrate the flammability of wax vapor, the formation of soot due to incomplete combustion, and the condensation of unburnt wax. The video concludes with a demonstration of a candle burning out when covered with a glass, highlighting the role of oxygen in combustion.

What are the two main components of a candle?

• Hydrogen and carbon

• Oxygen and carbon dioxide

• Flame and smoke

• Wick and wax

Which type of hydrocarbons are found in paraffin wax?

• Gaseous hydrocarbons

• Liquid hydrocarbons

• Short-chain hydrocarbons

• Long-chain hydrocarbons

Why are waxes solid at room temperature?

• They have short hydrocarbon chains

• They are made of gases

• Their long hydrocarbon chains are tangled

• They contain a lot of water

What happens to the wax when a candle is lit?

• It becomes a liquid and stays in the wick

• It vaporizes into gas

• It evaporates completely

• It turns into a solid

What is the main reaction occurring in a burning candle?

• Photosynthesis

• Evaporation

• Condensation

• Combustion

How can a candle be relit without the flame touching the wick?

• By holding a flame above the wick

• By adding more wax

• By using a special match

• By blowing on the wick

What is soot primarily composed of?

• Carbon

• Hydrogen

• Nitrogen

• Oxygen

What happens during incomplete combustion?

• Carbon is produced

• No energy is released

• Only water vapor is produced

• All wax is burned completely

What is observed when a candle is covered with a glass?

• The wax melts faster

• The flame grows larger

• The candle burns indefinitely

• The flame extinguishes due to lack of oxygen

What collects on the inside of the glass when a candle burns out?

• Unburnt wax

• Soot

• Water vapor

• Carbon dioxide