## W for BFCl2 in the lecture example

Boltzmann Equation for Entropy: $S = k_{B} \ln W$

Yutian Zhao -1J
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### W for BFCl2 in the lecture example

in the lecture, for the last example to calculate the W of BFCl2, if there are four moles of this molecules, does that mean w= 3^4NA? and therefore S=4Rln3? I am a little bit confused. Thanks!

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### Re: W for BFCl2 in the lecture example

It would be 3^4A, because you need to consider the shape of the molecule. It's trigonal planar so there are three different places the atoms can bound to; therefore your equation would be 3^NA. The question states in the beginning that there are 4 moles of this molecule; therefore it's 3^4A. S= Kb ln(w), and in this particular problem S= Kb ln(3^4A), you can bring out the 4A because of log properties to make it S= 4AKb ln(3). In lecture Dr. Lavelle said that when you multiply Avogadro's constant with Boltzmann's constant you get R; therefore, the equation becomes S= 4R ln(3).

Hope this helps.

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