How to make a magnesium sulphate paste?
Simply mix your epsom salts with a small amount of water - a little at first -- and stir until it becomes a paste. You can apply it directly, or as part of a poultice.
Why does magnesium displaces copper from copper sulphate?
This is a simple displacement reaction - the more reactive magnesium displaces the less reactive copper from a solution of its salt. .... magnesium + copper sulphate ---> copper + magnesium sulphate Mg + CuSO4 ----> MgSO4 + Cu the blue colour of the copper sulphate will disappear and the silver coloured magnesium will be replaced by brown-red copper metal. Hope this helps. :)