For my year 7 homework i have had to write a poster about pyhsical and chemical changes when a candle is alight. We have had to use certain vocabulary and one is evaporation. I know what this term means but don't know what evaporates when a candle is alight? Can someone please tell me what evaporates when a candle is alight and burning??????? Is it the gas made from the burning wick????

doesn't the wax melt, and then the heated liquid vaporizes, thence the gas burns in the atmosphere?

The candle burning breaks apart the hydrocarbons comprising the candle and forms water which it immediately evaporates.

Yes, when a candle is alight and burning, a process called evaporation occurs. However, in the case of a candle, it is not the gas made from the burning wick that evaporates. Instead, it is the liquid wax that evaporates.

To understand this, let's break it down step by step:

1. When the candle is lit, heat is generated from the flame. This heat causes the solid wax in the candle to melt, turning it into a liquid.

2. As the liquid wax heats up, it begins to vaporize and turn into a gas. This process is called evaporation.

3. The heat from the flame also causes the wax vapor to rise, creating the visible flickering flame that we see.

4. The vaporized wax mixes with oxygen from the air and undergoes combustion, which is a chemical change. This combustion process produces heat, light, and carbon dioxide gas.

So, while there is gas produced from the burning wick, it is not the gas that evaporates. Evaporation refers specifically to the process of the liquid wax turning into a gas.

When creating your poster, you can illustrate this process by showing a candle with arrows indicating the melting of the wax, followed by the evaporation of the liquid wax, and finally, the combustion of the wax vapor.