Post-Module Question #29  [ENDORSED]

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Karen Ung 2H
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Post-Module Question #29

Postby Karen Ung 2H » Sat Oct 14, 2017 3:33 pm

"Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 10^5 m.s-1. The work function for sodium is 150.6 kJ.mol-1.

29) How much energy is required to remove an electron from one sodium atom?"

I believe the question asks for the work function, but I'm confused as to why the answer is not 1.506 x 10^5 J. I'm not sure what I'm missing.

Vincent Kim 2I
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Re: Post-Module Question #29  [ENDORSED]

Postby Vincent Kim 2I » Sat Oct 14, 2017 4:16 pm

You're right to be using the work function, but the units are wrong. The question asks for how much energy is required to remove an electron from one sodium atom.

This means that you need to divide 1.506 x 10^5 J.mol-1 by avogadro's number (6.022 x 10^23).

It should give you 2.501 x 10^-19 J.


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