Compound and Mixture

What's the difference between a compound and mixture?

A compound made up of two chemically combined elements, and are only formed by a fixed ratio. The compound will also most probably lose the inital properties from its constituents and they can only be separated by chemical means.

A mixture, however, is made up of two physically combined elements. They can be mixed in varying ratios and do not have fixed properties like compounds. The properties of a mixture are the same as the properties of its constituents.

To prove the difference between the two, we conducted an experiment using iron fillings and sulfur.

MAGNETIC TEST

Firstly, to prove that mixtures can be separated by physical means, we:
1. Mixed one teaspoon of each element on a piece of filter paper using a stirrer
2. Used a magnet, placed below the filter paper and tried to separate the iron fillings (since it is magnetic) from the non-magnetic sulfur

It was a success, because eventually the iron fillings were completely separated. Then, we moved on to prove that the property of a mixture is the same as its constituents.

WATER TEST

Since sulfur cannot float, we:

1. Mixed the iron fillings and sulfur together using a stirrer on a piece of filter paper

2. Poured the mixture into a test tube filled with water

3. Used a clean stirrer to mix the mixture in water and left it to settle for about 45sec

4. Observe the elements in the test tube

What we observed:

After the whole thing, we observed that the sulfur floated while the iron fillings sank

Since sulfur alone will indeed float and iron filllings alone would sink, we could more or less confirm our findings, but of course we had to be fair and try it with a compound.

Firstly, we had set up our bunsen burner and poured one teaspoon of sulfur and half a teaspoon of iron fillings into a crucible, which we had then placed on top of the bunsen burner for 10 minutes. Example of our set-up below:

After the 10 minutes, let it cool for about a minute then use the tongs to transfer the compound onto a piece of filter paper. 

The compound

"Transfer the compound onto a piece of filter paper"

Next, repeat the Magnetic test. We had observed that the compound was no longer magnetic. Only iron fillings were attracted to the magnet (as we had put too much). This proves also that a compound is only formed by a fixed ratio.

We had also conducted the water test. Now the compound sunk to the bottom of the test tube. Hence, we can conclude that the compound will also most probably lose the inital properties from its constituents.