## thermodynamics!!

PCl5 (g) ---> PCl3 + Cl2

for the reaction above, delta H = +22.1 kilocalories per mole at 25 degrees celcius.

a. does the tendency of reactions to proceed to a state of minimum energy favor the formation of the products of this reaction? explain

b. does the tendency of reactions to proceed to a state of maximum entropy favor the formation of the products of the reaction? Explain

c. state whether an increase in temperature drives this reaction to the left, to the right, or has no effect.
Explain

d. State whether a decrease in volume of the system at constant temperature drives this reaction to the right, to the left, or has no effect. Explain

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### PCl5 (g) → PCl3 + Cl2 a)

PCl5 (g) → PCl3 + Cl2

a) Is this an endothermic or exothermic reaction? If heat is released (exothermic) then the products are more stable. If heat is absorbed (endothermic) then the starting material is more stable. (Clue: The sign of ∆H tells you this)

b) Gibbs free energy (if you know what that is, if not then you can just explain it like so) tends to favour an increase in entropy (chaos). As Cl2 is a gas and PCl3 is a liquid I think this beats PCl5 - ie more chaos is found in the products, to entropy is higher there (my thermoD is a bit rusty, but I'm sure that's right, unless you take degrees of freedom into account, in which case it might be there other way around?)

c) An increase of temperature = le chatilier (sp?) principle. If it's exothermic, the reaction tends to go backwards, to cool down the increased temperature, if it's endothermic, then it will drive the reaction forward (so you need to use ∆H again ;) )

d) ∆G = VdP - SdT (Gibbs again :) ) - constant pressure means dP is going to be zero, so....

Nice question

Thanks for share

### I am very thank full to you

I am very thank full to you

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