CHEMISTRY 3. In a 400 mL container, 2 mol of gaseous PC15 are introduced at a certain temperature. This gas decomposes according to the reaction below, and equilibrium was reached when 20% of the phosphorus pentachloride reacted % in moles). The equilibrium constant, Kc, under these conditions, is: PC15(9) =PC13(g) + Cl2(g) R = 0.25 4. A proposed method for collecting solar energy is to use this energy to heat sulfur trioxide to 800C, causing the reaction: SO3(g) = SO2(g) + O2(g) The compounds SO2(g) and 02(g), thus produced, are introduced into a heat exchanger of volume corresponding to 1.0 L and recombine, producing SO3(g) and releasing heat. If 5.0 moles of S03(g) undergo 60% dissociation at this temperature, what is the value of Kc? R = 1.84