# The Naked Scientists Forum

### Author Topic: What is meant by the term atomic percentage?  (Read 14087 times)

#### Paul Mather

• Guest
##### What is meant by the term atomic percentage?
« 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?
« Last Edit: 29/06/2010 13:56:20 by chris »

#### Atomic-S

• Hero Member
• Posts: 935
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##### Re: What is meant by the term atomic percentage?
« Reply #1 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.
« Last Edit: 13/06/2010 04:44:32 by Atomic-S »

#### robinhoods123

• First timers
• Posts: 1
##### Re: What is meant by the term atomic percentage?
« Reply #2 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.

#### The Naked Scientists Forum

##### Re: What is meant by the term atomic percentage?
« Reply #2 on: 29/06/2010 10:48:13 »