Page 21 - Curriculum Visions Dynamic Book

 The tube can then be taken from the flame and the red glow will spread up the tube without further heating. This is because the chemical reaction taking place, caused by heating, itself releases heat that in turn keeps the reaction going as long as there is
still elemental iron and sulphur in the tube.
 When the reaction is over, there is a brown coke-like compound in the tube. This is iron sulphide. Compare it with the crystals on
pages 18 and 19 to see that compounds can have the same chemical formula but look remarkably different. Iron sulphide
has no magnetic properties, showing that the compound shares little in common with the starting materials from which it was made.
EQUATION: Laboratory production of iron sulphide
Iron + sulphur ➪ iron sulphide Fe(s) + S(s) ➪ FeS(s)
When heated in a test tube the iron and sulphur combine to form the compound iron sulphide, which has no magnetic properties.
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