Equilibrium – Beginner’s Problems…Really
1.
Two moles of gaseous NH3 are introduced into a 1.0L vessel and allowed to undergo partial decomposition at high temperature
according the reaction:
2NH3(g)
N2(g) + 3H2(g) At equilibrium, 1.0mol of NH3(g) remains. What is the value of the
equilibrium constant?
2.
One mole of H2(g) is to be reacted with one mole of I2(g). Assuming the equilibrium constant is 45.9, what will be the final
concentration of the chemical components in a 1L bottle at 490C?
3.
Suppose a tank initially contains H2S with a pressure of 10.0 atm at 800K. When the reaction : 2 H2S
Has come to equilibrium, the partial pressure of S2 vapor is 2.0 x 10-2 atm. Calculate both the kp and the kc.
4.
The equilibrium constant, kc, for the reaction: N2O4(g)
2NO2 At 25C is 5.88 x 10-5. Suppose 20.0g of N2O4 is placed
in a 5.00L flask at 25C. Calculate the number of moles of NO 2 present at equilibrium and the percentage of the original N2O4 that
is dissociated.
5.
Solid NH4HS(s) is introduced into an evacuated flask at 24C. The following reaction takes place: NH4HS(s)
At equilibrium the total pressure for the products is 0.614atm. What is the Kp for this equilibrium at 24C?
6.
At 2000C the equilibrium constant for the reaction: 2NO(g)
N2(g) + O2(g) is 2.4 x 103. If the initial concentration of NO is
0.500M, what are the equilibrium concentrations of NO, N2, and O2?
7.
The equilibrium constant kc for the dissociation of iodine is 3.76 x 10-3 at 1000K.
I2(g)
2I(g)
Suppose
1.00mol of I2 is placed in a 2.00L flask at 1000K.What are the concentrations of I2 and I when the system comes to equilibrium?
8.
At 21.8C, Kc = 1.2 x 10-4 for the equilibrium: NH4HS(s)
NH3(g) + H2S(g) Calculate the equilibrium concentrations of NH3
and H2S is a sample of solid NH4HS of placed in a closed vessel and decomposes until equilibrium is reached.
9.
At 450C, 3.60mol of ammonia is placed in a 2.00L vessel and allowed to decompose to the elements: :
2NH3(g)
N2(g) + 3H2(g) If the experimental value of Kcis 6.3 for this reaction at this temperature, calculate the
equilibrium concentration of each reagent.
2H2(g) + S2(g)
NH3(g) + H2S(g)
10. At 900K the following reaction has Kp = 0.345: 2SO2(g) + O2(g)
2SO3(g) In an equilibrium mixture the partial pressure of
SO2 and O2are 0.215atm and 0.679, respectively. What is the equilibrium partial pressure of SO 3in the mixture?
11. Solid ammonium carbamate, NH4CO2NH2, decomposes at 25C to ammonia and carbon dioxide according the equations:
NH4CO2NH2
2NH3(g) + CO2(g) the equilibrium constant, Kp, for the decomposition at 25C is 2.3 x 10-4. At 25C, 7.5
grams of NH4CO2NH2 are sealed in a 10.0L flask and allowed to decompose.
a. What is the total pressure in the flask when equilibrium is established?
b. What percentage of NH4CO2NH2 decomposed?
c. Can you state from the data collected that the decomposition took place slowly?
12. Solid ammonium iodide decomposes into ammonia and hydrogen iodide gases at sufficiently high temperature.
NH4I(s)
NH3(g) + HI(g) The equilibrium constant, Kp, for the decomposition at 637K is 0.215. Fifteen grams of ammonium
iodide is sealed in a 5.0L flask and heated to 673K. What is the total pressure in the flask at equilibrium? How much ammonium
iodide decomposes?
13. Phosphorus pentachloride gas can be produced by reacting phosphorus trichloride and chlorine gases at a certain temperature.
PCl3(g) + Cl2(g)
PCl5(g) At that temperature, Kp = 0.42. What is the partial pressure of chlorine gas at equilibrium if the
initial partial pressures are PCl2 = 0.500atm and PPCl3 = 1.00atm?