Investigating mixtures and compounds

My friends and I did some experiments to investigate the properties of a mixture and a compound. The experiment needs tripod stand, evaporating dish, glass rod, wire gauze, Bunsen burner, sulfur powder, iron filings, filter paper and a magnet wrapped in a small piece of paper.
Both sulfur and iron are elements. When they are mixed, a mixture of iron and sulfur is formed and when they are heated together, a compound, iron sulfide is formed.
Observing Elements
1. Place the sulfur powder on a piece of filter paper. The sulfur is in a form of yellow powder.
2. Wrap on end of the magnet with a small piece of paper the move the magnet close to the sulfur powder. The sulfur powder is not being attracted by the magnet.
3. Place the iron filings in an evaporating dish. The iron filings are in a form of black powder.
4. Move the magnet close to the iron filings. The iron filings are being attracted to the magnet.
Observing a mixture
5. Pour the sulfur powder into the evaporating dish of iron filings. Mix it thoroughly with the iron filings using a glass rod. The mixture is a mixture of yellow and black powder.
6. Move the magnet close to the mixture. Only the iron filings are being attracted to the magnet.
Observing a compound
7. Heat the evaporating dish over the Bunsen flame until no more change occurs. Allow the evaporating dish to cool. The compound is in a form of a dark grey powder.
8. Move the magnet close to the compound. The compound is not attracted to the magnet.

I think that the mixture of iron and sulfur has the properties of iron and sulfur because no heat is released or taken in and the basic appearances of black and yellow powder are still evident.
Heat is needed for a compound to form.
I think that the compound formed from iron and sulfur does not have the properties of iron and sulfur because the colour is entirely different from its constituent components and no parts of the compound is attracted to the magnet.

Hence, I can conclude that heat is not needed to form a mixture but heat is needed to form a compound. A mixture has the properties of its constituent elements while a compound does not have the properties of its constituent elements. A mixture can be separated into its elements by physical methods but a compound cannot be separated into its elements by physical methods.