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Offline chilli

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question
« on: March 29, 2016, 06:18:19 AM »
hello all!
I was given this question:
the energy needed to make 1 Cs+ ion is 3.89eV, what is the energy amount needed (in Joules) in order to get 2.5 moles of Cs ions

this is how I solved it but it doesn't feel right maybe I missed something in class, what is wrong with my solution?

 2.5 mole Cs+ = 1.505x10^24ions

 3.89eV x 1.60x10^-19 = 6.224x10^-19J

 6.224x10^-19J x 1.505x10^24= 936712J

I appreciate any help

 

Offline Borek

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Re: question
« Reply #1 on: March 29, 2016, 06:43:08 AM »
Haven't checked numbers but the logic looks correct.
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Offline chilli

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Re: question
« Reply #2 on: March 29, 2016, 06:52:28 AM »
really? can joule results often come in such large numbers? (excuse my silly questions I don't have the feel for this scale yet, is it something you get later?)

Offline Borek

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Re: question
« Reply #3 on: March 29, 2016, 07:33:42 AM »
Hundreds of kJ per mole is a quite common number when it comes to chemical reaction energetics.
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Offline chilli

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Re: question
« Reply #4 on: March 29, 2016, 07:46:36 AM »
ty very much!

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