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UPSC Combined Geo-Scientist

Chemist

  • 3 descriptive papers
  • 200 marks each
  • 3 h per paper

Mains Paper III covers analytical and organic chemistry.

UPSC Combined Geo-Scientist, Mains · 2021 · Mains Paper III

Q5(c). MgSO₄·7H₂O in a sample from the TG mass loss

Question

The TG curve of 2.9 mg of a sample containing MgSO₄·7H₂O (molecular weight 246) exhibited a weight loss of 0.6 mg at a temperature of 105 °C. Calculate the % of MgSO₄·7H₂O in the sample.

Answer in brief

40.4 % if all seven H₂O are lost; 47.1 % if only six H₂O are lost at 105 °C.

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Topic notes: thermogravimetry, DTA and the calcium oxalate thermogram, with every Civil Services, IFoS and Geo-Scientist PYQ →

CoversthermogravimetryTG curvewater of crystallisationMgSO4·7H2O

All parts of Question 5