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NA 2 SO 4 XH 2 O ON HEATING SUFFERS A LOSS OF WEIGHT OF 56% THEN FIND X , MOL.WT ?

NA2SO4XH2O  ON  HEATING  SUFFERS   A LOSS  OF WEIGHT  OF  56%  THEN  FIND  X , MOL.WT ?                                                                                                                                                  

Grade:12

2 Answers

sasha sasha sasha
18 Points
14 years ago

Na2SO4.XH2O -> Na2SO4 + X H2O (BECOMES ANHYDROUS)

 

1MOLE              ==      1      == X MOLES            (== MEANS REACT)

 

THUS,

100/(142+18 X) == 1  == 100 X/(142+18 X)MOLES

AND WE HAVE 56/18 MOLES OF H2O (AS 56% LOST GOES IN H20).

EQUATING THEM YOU GET X = 10 MOLES .....

AND THUS CALCULTE MOL WT. YOURSELF.

Ramesh V
70 Points
14 years ago

on heaing it looses all water molecules

let n water molecules be present in the compound before heating

its mol. wt. is : 18n + 142

loss in mol wt after heating : 18n

18n/(142+18n) = 54/100

on solving fo rn gives : n=10

the compound is NA2SO4.10H2O

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regards

Ramesh

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