Materials science vacancies example problem

Worked example problem solution and tutorial for vacancy concentration calculation. Materials science tutorial.

[GalibFida]

thank you so much for actually solving a problem! all the videos by other channels just kept explaining the concept

[kieralerado]

Sorry but how to calculate the exp in calculator?? I stuck there

[tetyanazlatova]

what does the fraction of vacant sites percentage is actually saying? what percentage of what what number is empty?

[divyanshsharma]

Can't be formula N=N' exp(-Hf/2RT) be used in this question?
If not then why?
And is N in the given formula no of vacancies or concentration of vacancies?

[muhammadazamuddinbinazlan]

So where does 6.023x10^23/mol comfrom?

[sj-bgup]

why is the volume multiplied by avagadro?

[fxtaru]

lol the question you use is the same as my tutorial question XD

[millanmarkjustinem.]

Does the unit for avogadro's number is atom/mole?

[GeneAmarado]

The final answer is supposed to be 1.17 x 10^20

[sgdr]

why does my calculated value differ from yours?