Science, asked by p3viraninsukala, 1 year ago

What does 2(CaSO4).4(H2O) give upon heating? I know how to write the actual formula which is CaSO4.2(H2O)---CaSO4.1.5(H2O) SO dont tell me that again and again. What i want to know is that the part in bolds can't form naturally, is the way i have written correct?

Answers

Answered by kvnmurty
0
2(Ca SO4) . 4 (H2O)  is hydrous calcium sulphate or Gypsum.  Two Molecules of water are associated with a molecule of Calcium Sulphate in the crystal structure of Gypsum.

When Gypsum is heated beyond 100 °C, the water molecules get vaporized and escape from the gaps between molecules. So around 150°C we get Plaster of Paris or Calcium Sulphate Hemi hydrate.

 correct:  2(Ca SO4) . H2O     or   (Ca SO4) . 1/2 (H2O)   or
                   (Ca SO4)2 . H2O

This means that two molecules of Calcium Sulfate share one molecule of water in the gap between them.  If Plaster of Paris is heated even more to very high temperatures, then the compound becomes anhydrous totally.

  This compound Plaster of Paris does not occur naturally, as there is humidity in the atmosphere and in soil. The moisture is absorbed and so we find Gypsum. 

  Ca SO4 . 2 (H2O) ==> heat ==> (Ca SO4) . 1.5 (H2O) + 0.5 H2O

   This happens when Gypsum is heated.  The above Gypsum with 1.5 molecules of water, will lose water on heating or gain water if moisture is there. It does not remain as it is.  So it is not found in nature like that.

  You can write Ca SO4 . n (H2O) ,   with   n ranging from 0.5 to 2, the n depends on moisture and temperature.

Similar questions