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Topic: is carbon the reference element?  (Read 4017 times)

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tashkent

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is carbon the reference element?
« on: November 21, 2004, 07:16:19 AM »
Greetings everyone!

I would like to ask if carbon is used as a reference for all elements?  I've encountered this question in my GRE Chemistry exam, and I answered Hydrogen instead of carbon.  My friend told me that it should be carbon, because 14C is used for radiocarbon dating.  Is he correct?

Hope to receive replies from u guys.  Thanks so much.

Regards,
Tashkent

Offline Donaldson Tan

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Re:is carbon the reference element?
« Reply #1 on: November 21, 2004, 08:46:23 AM »
carbon-12 is used as a reference to all elements. the relative molecular mass of all elements are measured with reference to 1/12 the mass of the carbon-12 atom.
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Re:is carbon the reference element?
« Reply #2 on: November 24, 2004, 11:22:58 PM »
Yes, to put it another way, a carbon-12 atom has a mass of exactly 12 amu by definition.  So you really have to think of it as 1 amu is 1/12 the mass of a carbon-12 atom, not a carbon-12 atom has a mass of 12 amu.

It's a subtle difference.

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