Because water present in it gets evaporated due to heating.
Hope it helped u.
(a) The green iron compound is ferrous sulphate. (c) When ferrous sulphate crystals are heated, they lose water of crystallisation and become colourless. On further heating, the ferrous sulphate crystals decompose to form ferric oxide, sulphur dioxide and sulphur trioxide.
the direction of the conventional current is from positive to the negative termianl of the battery.
where as the electrons flow from the negative terminal of the battery to the positive terminal of the battery is exactly opposite to the conventional direction.
here the conventional current is but from the olden days we are following direction conventionally as the previous scientists belived that the positive charges moves always, but the positive charges cannot move in the solids.
the girls know are smart enough..