![On heating a sample of 25 mg hydrated compound (molecular weight = 250 g/mol) in thermogravimetric analysis, 16 mg of dehydrated compound remains](https://www.gkseries.com/blog/wp-content/uploads/2023/08/On-heating-a-sample-of-25-mg-hydrated-compound-molecular-weight-250-g-mol-in-thermogravimetric-analysis-16-mg-of-dehydrated-compound-remains.jpg)
Q. On heating a sample of 25 mg hydrated compound (molecular weight = 250 g/mol) in thermogravimetric analysis, 16 mg of dehydrated compound remains. The number of water molecules lost per molecule of hydrated compound is .
(Molecular weight of water = 18 g/mol)
Solution:
25 mg Compound contains (25-16) g of Water = 9 g of water,
Using,
No. of moles = Given Mass / Molecular Mass
No. of moles = 250 g of the compound will contain 90 g of water; and
250 g of Water will contain = 90 / 18 moles of Water = 5 moles.