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Topic: Relative Formula Mass  (Read 5683 times)

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Offline Viral

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Relative Formula Mass
« on: October 11, 2009, 04:39:03 PM »
Calculate the relative formula mass of:

(NH4)2 SO4 FeSO4 6H20

I got 392, but my friend got 312. Who is right and why?
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Offline Borek

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Re: Relative Formula Mass
« Reply #1 on: October 11, 2009, 05:04:31 PM »
No idea why, but you are right.
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Offline DrCMS

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Re: Relative Formula Mass
« Reply #2 on: October 12, 2009, 11:32:31 AM »
You are right because you did the maths correctly.

I can only assume your "friend" did the following:

((14+4)*2)+32+(16*4)+56+32+(16*4)+(6*1*2)+16 = 312

rather than what you did the correct way:

((14+4)*2)+32+(16*4)+56+32+(16*4)+(6*(2+16)) = 392
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