Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: Paul Mather on 24/05/2010 00:30:03

Title: What is meant by the term atomic percentage?
Post by: Paul Mather on 24/05/2010 00:30:03

Paul Mather  asked the Naked Scientists:
   
Hello... I was wondering if you would be able to help with the follow question...

Cementite: consider cementite. Calculate the amount of carbon in Cementite (1) as atomic % (2) as weight % [atomic weights Fe 56, c 12]. Place cementite on the Fe-C phase diagram; explain the nature of its appearance on the diagram, and comment on the nature and properties of cementite. Cementite is a key part of pearlite- how does it contribute to the structure of pearlite?

I totally understand the question apart from the atomic % and the weight %, if you could help and provide a worked solution so i can begin to understand the numbers i would be extreamly grateful as this part is not my string point. I believe the % wt of carbon for this is 4.3%.
 
Thanks again, kind regards
 
Paul.

What do you think?

Title: Re: What is meant by the term atomic percentage?
Post by: Atomic-S on 13/06/2010 04:42:53

Weight % = 100 * weight of one component / weight of entire sample.

Atomic % = 100 * number of atoms of one component / total number of all atoms in sample,
         = 100 * number of moles of one component / number of moles of all components.

Weight of component / molecular (or atomic for single element) weight of that component = number of moles of that component.

Title: Re: What is meant by the term atomic percentage?
Post by: robinhoods123 on 29/06/2010 10:48:13

As far as i think the details provided in brackets are atomic weight of Copper and zinc and they are combined to make brass (allow) in weight percentage (wt%) given.