whats happens to the candle as it burns? [why does it get smaller?]?

Question

This is for my honors bio. homework

and i like dont get it
she said hint: its not melting.


and i dont
know what it is so
help please :]

is this an example of a physical or chemical change?


why?

Answer 1

The wax, a hydrocarbon (C-H bonds), burns, consuming oxygen from the air, and creating carbon dioxide, water, heat and light (energy is released in the reaction). The heat melts some of the wax, but much of the wax is burned to create heat and light.

Answer 2

You are right --- the candle first gets melt when it burns. Melting of the wax is a very important link in the process of burning --- but burning is not only melting.
Do you know where is the hottest spot in the candle flame? It is the blue colored region, then the orange colored region, then, of course, outside the orange colored region.
When the candle burns, it first melts. The liquified fuel (wax) then moves upward through the wick via capillary action. The liquified fuel is then vaporized to burn within the candle's flame. Since the wax is mainly hydrocarbons, the product is water (H2O) and carbon dioxide (CO2) vapor at that high temperature, and thus you may not be able to visualize the burning product. Therefore, the candle gets smaller as it burns.
You may see the end of the wick gets burned when there is not enough supply of the melted wax fuel via capillary action.

Answer 3

The heat of the flame at the wick causes a small amount of the wax to melt, and capillary action (like a sponge) causes the liquid to travel up the wick.
Candle wax is flammable, so when the liquid reaches the flame it burns - that is the fuel for the flame.
The candle gets smaller because the material of the candle is being burned to fuel the flame.

So she's right, its not melting so much as its burning (the wax melts a little right by the wick but that's not why it gets smaller).

Answer 4

The candle (wax) is the fuel for the flame. Think of an oil lamp. The oil wicks up the wick and is burned by the flame. The wax of a candle does the same thing.

Answer 5

when the candle is burning the wax is reacting with the oxygen in air to form carbon dioxide and this gas escapes so the candle gets smaller because mass is conserved in all chemical reactions.

Answer 6

out of feul