PCl5(g) --> <-- PCl3(g) +Cl2(g)
(--> <-- means a reversible reaction)
has been studied by mixing one mole of PCl3 and one mole of Cl2 at 1 bar total pressure, allowing them to react and noting the pressure attained at equilibrium; the volume of the container is fixed.
The observed equilibrium pressures, in bar, were 0.53 and 0.82 at temperatures of 400 and 500 K, respectively.
Assuming that all the species behave as ideal gases, determine the mole fraction of PCl5 present at equilibrium in each case, and consequently calculate K(p) and ΔG(standard) at the two temperatures.
Assuming that it is approximately constant over the temperature range in question, estimate ΔS(standard) for the reaction. Is the value in accordance with what you would expect ?
(K(p) is the pressure equilibrium constant, G(standard) is the standard molar Gibbs energy, S(standard) is the standard molar entropy).
Rep for the first one to complete the whole lot correctly...it's hard, and long.
EDIT: this has now been moved to the correct place. Sorry.