chemistry question ppl pls help!!?

Question

ok this is a chemistry question i am really stuck with~~~~~ahh

is melting of wax a chemical change of a physical change??

you see melting means is physical change but it involves burning so need oxygen so is combustion so is chemical change so which is it!!!!!!!! pls help sobsob

Answer 1

Melting of wax is just that: melting. Where does it say it has do be done through combustion? Even if the wax that is melting is the result of combustion, this is not the wax that is burning that is asked about; that wax melts (like in a candle) THEN burns.
If someone asked about "burning a candle" then one could say that there is both physical AND chemical change involved. But as long as you restrict yourself ONLY to the melting part, then this is purely a physical change.

Answer 2

Good question! I see your confusion here. Actually, when you add fire to wax then it's a bit of both. Wax will melt without fire though so just melting wax is a physical change when fire isn't involved. Let me try to explain.

1. Fire is a chemical reaction. It needs oxygen and another combustible material in order to occur. Oxygen is a VERY reactive element and when it reacts with another element or compound to create new compounds it gives off heat (called an exothermic reaction).

2. Candle wax is not an element but a mix of compounds. The elements that make up candle wax aren't all bonded chemically at the elemental level. A lot of it is just stirred in real well so that you can't see it. It's not attached to anything, just being held there by other compounds that differ in structure. This is called a homogeneous solution. If you mix oil and water together and shake very very well, you may get some of the oil not to float immediately to the top. Some of the oil gets suspended in the water. However, the two do not chemically combine, they just mix.

The best way to demonstrate this would be to mix oil and water together really well, then freeze it fast before the oil can fully separate from the water.

Once you have done this, you effectively have a candle. The oil in the frozen water will burn once exposed to the air, melting the ice causing more oil to be exposed. It won't burn all that fast (just like a candle) because all the oil in the water doesn't get exposed at once. This is due to the time it takes the fire from the little drops of oil to melt the surrounding ice.

So, the answer to your question is it's both! It is a physical change because the heat from the fire melts the rest of the candle that is less flammable. The fire is a chemical reaction to compounds in the wax that are more combustible than the rest of the wax.

Sorry for the length but who would have thought that just letting a candle burn is actually a complicated chain of events.

Answer 3

It's physical change as on cooling melted wax gets converted into solid wax

Answer 4

Physical change. You don't need burning to melt wax, no flame need be involved, just enough heat to melt it. You could leave it on a windowsill in the hot sun or sit it on top of your heater or wherever it's warm enough.

Answer 5

It's a physical change, it changes shape and density and all that jazz.

If it was a chemical change it would no longer be wax but another substance. It wouldn't have the same chemical properties as wax.

Answer 6

Physical change. Melting does not change the molecular structure of wax. Changes in molecular, atomic or ionic structure would be defined as chemical change.

Answer 7

you can melt wax on the stove in a pot. No Oxygen needed with an electric stove.

You melt it, it's liquid wax. But it is still wax.
Good enough hint?

Answer 8

i think its still a physical change because there hasn't been any change in the chemical structure of the compound only its physical state

Answer 9

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