Quiz 513 102 (Equilibrium) Name ID
1. For the reaction PCl5(g) PCl3(g) + Cl2(g), Kc = 0.0454 at 261 oC. If a vessel
is filled with these gases such that the initial concentrations are [PCl3] = 0.50 M,
[Cl2] = 0.20 M, and [PCl5] = 4.50 M, in which direction will a net change occur?
2. When a 0.0200-mol sample SO3 is introduced into an evacuated 1.52-L vessel at
900 K, 0.0142 mol SO3 is found to be present at equilibrium. What is the value
of Kp for the dissociation of SO3(g) at 900 K?
2 SO3(g) 2 SO2(g) + O2(g) Kp = ?
3. A 5.00-L evacuated flask is filled with 1.86 mol NOBr. At equilibrium at 25 oC,
there is 0.082 mol of Br2 present. Determine Kc and Kp for the reaction
2 NOBr(g) 2 NO(g) + Br2(g)
4. Ammonium hydrogen sulfide, NH4HS(s), used as a photographic developer, is
unstable and dissociates at room temperature.
NH4HS(s) NH3(g) + H2S(g) Kp(atm) = 0.108 at 25 oC
A sample of NH4HS(s) is introduced into an evacuated flask at 25 oC.
What is the total gas pressure at equilibrium?
5. 1.00 x 10-3 mol PCl5 is introduced into a 250.0-mL flask, and equilibrium is
established at 284 oC : PCl5(g) PCl3(g) + Cl2(g). The quantity of Cl2(g)
present at equilibrium is found to be 9.65 x 10-4 mol. What is the value of Kc for
the dissociation reaction at 284 oC?