October 22, 2020, 08:45:20 AM
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### Topic: I have no idea how to work out this question?  (Read 203 times)

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##### I have no idea how to work out this question?
« on: September 23, 2020, 11:09:51 AM »
Element W has two natural isotopes: W-10 (10.013amu) and W-11 (11.009 amu)
Calculate the atomic mass of element W given the abundance of W-10 is 19.66%

I thought that I needed abundance for both isotopes to solve the atomic mass? I’m really bad at Math and Chemistry... I thought I was understanding how to solve atomic mass and now I can’t figure out this question. I asked my prof for help but he used an example where we were given abundance and amu for all the isotopes and just had to use the average atomic mass formula.

TIA

#### DrCMS

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##### Re: I have no idea how to work out this question?
« Reply #1 on: September 23, 2020, 12:01:10 PM »
If this element has only 2 isotopes and you are given the abundance of one of them can you not see how to calculate the abundance of the other one?

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##### Re: I have no idea how to work out this question?
« Reply #2 on: September 23, 2020, 01:58:48 PM »
No. I don’t know how to do that and my text book does not have examples?

#### Corribus

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##### Re: I have no idea how to work out this question?
« Reply #3 on: September 23, 2020, 02:25:14 PM »
Start by defining what "abundance" and "atomic mass" are. Can you relate the one to the other?

EDIT:

Quote
he used an example where we were given abundance and amu for all the isotopes and just had to use the average atomic mass formula
And this is exactly what you need to do here. You are just not given one piece of information, so you have to determine it for yourself.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman