The Equilibrium Constant.docx

1.

The equilibrium constant, Kc, for the reaction: SO3(g) + NO(g) ⇌ NO2(g) + SO2(g) was found to be 0.500 at a certain temperature. If 0.240 mol of SO3 and 0.240 mol of NO are placed in a 2.00 dm3 container and allowed to react, what will be the equilibrium concentration of each gas? SO3(g) + NO(g) ⇌ NO2(g) + SO2(g)

Initial Conc. Change Equil. Conc.

SO3(g) 0.240/2 = 0.120 -x 0.120 - x

NO(g) 0.240/2 = 0.120 -x 0.120 - x

NO2(g) 0 +x x

[NO2 ][SO2 ] = 0.500 [SO3 ][NO] 𝑥2 = 0.500 (0.120 − 𝑥)2 𝑥 = 0.707 0.120 − 𝑥 𝑥 = 0.08485 − 0.707𝑥 𝑥 = 0.0497

𝐾𝑐 =

[SO3 ] = [NO] = 0.120 − 0.0497 = 0.0703 mol dm−3 [NO2 ] = [SO2 ] = 0.0497 mol dm−3

SO2(g) 0 +x x