posted by ChemGeek .
I am unsure of how to approach this question, any help would be greatly appreciated!
"2.085g of PCl5 were heated to 250°C in a 500mL vessel:
PCl5 (g) ⇌ PCl3 (g) + Cl2 (g)
Calculate the initial concentration of PCl5. At equilibrium the concentration of the chlorine is 0.018 mol L-1."
This is a weirdo question. The initial concn is
mols PCl5 = grams/molar mass
M = mols/0.500 = ?
The other numbers are not needed. They would be needed if you wanted the equilibrium concn of PCl5.