* Reactants: The candle wax (a hydrocarbon) and oxygen from the air.
* Products: Carbon dioxide (CO2), water vapor (H2O), and heat (light energy is also released, hence the flame).
Here's how it works:
1. The flame melts the wax near the wick.
2. The melted wax is drawn up the wick by capillary action.
3. The heat of the flame vaporizes the wax, turning it into a gaseous hydrocarbon.
4. This gaseous hydrocarbon reacts with oxygen in the air, a process called combustion.
5. This chemical reaction releases energy in the form of heat and light.
Key points to remember:
* The wax undergoes a permanent change in its chemical composition. It's not simply melting and reforming, it's reacting with oxygen to create new substances.
* The combustion process is exothermic, meaning it releases heat. This is why candles feel warm.
* The wax cannot be recovered from the products. The process creates entirely new substances (CO2 and H2O).
Therefore, burning a candle is a chemical change because it involves the formation of new substances with different properties than the original reactants.
