A mixture containing only iron (III) sulfide and iron (III) chloride is reacted with HCl. The iron sulfide reacts according to the balanced equation:
Fe2S3 + 6HCl--->2FeCl3 + 3H2S
The iron chloride does not react with HCl. When 5.0000g of this mixture is reacted with excess HCl, 420.25ml of hydrogen sulfide gas is collected, measured at 18.6C and an atmospheric pressure of 751.2 torr, using a water displacement method.
Calculate the number of moles of hydrogen sulfide gas collected in this experiment.