At 80C,Kc=1.87103 for the reaction PH3BCl3(s)PH3(g)+BCl3(g) (a) Calculate the equilibrium concentrations of PH3 and BCl3 if a solid sample of PH3BCl3 is placed in a closed vessel at 80C and decomposes until equilibrium is reached. (b) If the flask has a volume of 0.250L, what is the minimum mass of PH3BCl3(s) that must be added to the flask to achieve equilibrium