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Physical Chemistry

Hot goIITian

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6 Apr 2008 20:49:25 IST
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If the density of lake water is 1.25g/mL and
 
contains 92 g of Na+ ions per kg of water ,
 
calculate the molality of Na+ ions in the
 
lake?


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varsha valli g.'s Avatar

Blazing goIITian

Joined: 31 Jan 2007
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6 Apr 2008 21:18:39 IST
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is it 4m ???????
!!!!!!!!!!!!!!!

Hot goIITian

Joined: 23 Mar 2008
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6 Apr 2008 21:26:21 IST
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Yes but please explain the process.Is it related to given density.

Hot goIITian

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6 Apr 2008 21:37:04 IST
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Please reply soon
varsha valli g.'s Avatar

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6 Apr 2008 21:44:33 IST
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sorry for the late reply
d----density=1.25g
d=m/V
volume of water can b taken as 1000ml
m=1.25*1000g
in 1000g of water there is 92g of Na+
thus in 1.25*1000g------->1.25*92
substituting the values,
molality=1.25*92*1000/23*1.25*1000
=92/23=4m
hope this helps
!!!!!!!!!!!!!!

Hot goIITian

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6 Apr 2008 22:09:34 IST
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Is it neccesary to take the volume 1000mL?Can't we take another volume?
rohit's Avatar

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6 Apr 2008 22:38:21 IST
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u can take any other volume it wont affect the final answer
but generally we choose no such that they reduce our calculations



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