What kind of chemical change can you see when a candle burns?How can you tell it is a chemical change?

Answer 1

There is both physical and chemical change in a burning candle.

Firstly, the wax melts and then vaporizes. You can see the melt but it is hard to see the vapors.

It is actually the vapors that burn and undergo chemical change. In this case a hydrocarbon is reacting with O2 and forming CO2 and H2O. Since there are impurities in the candle wax, you may see some black smoke or soot.

One way to show that the vapor is burning (and not the melted wax) is to blow out the candle flame and bring a lit splint near (but not touching) the wick. The candle will reignite, because the vapors are still there