Question

Iron and sulphur if mixed form a mixture but if heated,form a compound.How are they identified(mixture or a compound)?

Answer 1

when they mixed it showed properties of the both iron and sulphur and have two types of particles, so it is called a mixture .
When heated, iron bonded with sulphur and forms a new substance iron sulphide which does not show the property of iron and sulphur
and has one type of particle , that's why it is called a compound