"Published in Vacaville, California, USA"
PCl5(g) dissociates into PCl3(g) and Cl2(g) when heated at 250°C and 1 atm. If the density of the gas mixture at equilibrium is 4.4 g/L, what is the fraction of PCl5(g) dissociated?
Solution:
Consider the chemical reactions above as follows
At equilibrium, there are PCl5(g), PCl3(g) and Cl2(g) gas mixture in 1 liter. If the volume of the reaction at equilibrium is 1 liter, then the number of moles of gas mixture at equilibrium is
At the start of the reaction, the volume is also 1 liter. The number of moles of PCl5(g) which is also the number of moles of gas mixture at the start of the reaction is
Hence, the amount of PCl5(g) dissociated or converted into PCl3(g) and Cl2(g) is
Therefore, the fraction of PCl5(g) dissociated is
