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Making a Compound

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Fig 1: Apparatus diagram
Fig 1


Sulfur and iron can be separated easily but if heated together they make a new compound that cannot easily be separated.


This practical shows pupils the differences between mixtures and compounds. In this example, a small amount of powdered iron and sulfur is mixed together in an ignition tube (not more than a quarter full). This mixture can easily be separated using a magnet because there are no chemical bonds between the two elements.

The mixture is then gently heated above a Bunsen burner until the mixture glows slightly. It is then removed from the flame for a few seconds and then reheated for a bit longer. It is left to cool.

The mixture will have turned into the compound iron sulfide and now cannot easily be separated into its former elements. The compound now has chemical bonds between the two elements and is no longer magnetic.

Equipment required (per set):

  • Ignition tube
  • Tongs
  • Magnet
  • Bunsen burner
  • Heatproof mat
  • Sulphur powder
  • Iron filings


 Wear eye protectionWear eye protection.

Consider using a fume cupboard, elsewhere good ventilation is essential.

The contents of this page are for information only. Please refer to CLEAPSS or ASE safety advice and/or publications before undertaking any preparation, practical experiment or using any equipment featured on this site or any other.