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2) A mixture of 1.90 moles of H2 and 1.90 moles of I2 were allowed to reach equilibrium at 710 K. The equilibrium mixture
was found to contain 3.00 moles of HI. Calculate Kp.
H2(g) + I2(g) 2 HI(g)

3) For the equilibrium below calculate Kp if pO2 = 102 kPa, pSO2 = 251 kPa, pSO3 = 508 kPa.
2 SO2(g) + O2(g) 2 SO3(g)

4) 2.00 moles of sulphur dioxide and 1.00 mole of oxygen were mixed and allowed to reach equilibrium in the presence of
a suitable catalyst under a total pressure of 500000 Pa. At equilibrium, 0.67 moles of oxygen were present. Find Kp.
2 SO2(g) + O2(g) 2 SO3(g)

5) 2.00 moles of X was heated to a temperature of 2000C until equilibrium was established under a total pressure of
8.00 x 107
Pa. At equilibrium, X was found to have undergone 20% dissociation. Calculate Kp.
X(g) Y(g) + 2 Z(g)

6) 2.00 moles of A was mixed with 2.00 moles of B and the mixture allowed to reach equilibrium at 500C. The
equilibrium mixture was found to contain 0.90 mole of A. Calculate Kp.
2 A(g) + B(g) 3 C(g)

7) In the following reaction at 700 K, the amount of each gas present at equilibrium is 0.960 moles of NO2, 0.040 moles of
NO, and 0.020 moles of O2. If Kp = 6.80 x 10-6
atm, what must the total pressure have been to achieve this particular
equilibrium mixture?
2 NO2(g) 2 NO(g) + O2(g)

8) Calculate the number of moles of each species at equilibrium if 0.50 moles of A and 0.50 moles of B are mixed at 500
K, given that Kp = 2.55 at this temperature and pressure = P (you will NOT need to use a quadratic equation to solve
this).
A(g) + B(g) 2C(g)

9) Calculate the number of moles of each species at equilibrium if 5.00 moles of CO2 and 1.00 mole of H2 are mixed at
1000 K, given that Kp = 0.72 at this temperature and pressure = P (you will need to use a quadratic equation to solve
this).
CO2(g) + H2(g) CO(g) + H2O(g)
Reply 1
With questions relating to equilibria constant, you want to draw out an ICE chart. This stands for Initial/Change/Equilibrium in terms of moles.

Write out your equation and under it draw a table where each chemical is a column and there are 3 empty rows. Label the rows (from top to bottom) initial, change, equilibrium. Fill in the information you already know (i.e. the question tells you the initial mols for the reactants, fill that in. The question tells you the equilibrium moles for the products, fill that in).

Once you have done that, fill in the change row. This is the difference between mols at initial and mols at equilibrium for each chemical. Look at the products--you start with 0 and then the question tells you how much there is at equilibrium. This should be enough info to work out the change. Then, using the molar ratio, figure out the change for everything else. For example: in the equation A + B -> C, the molar ratio is 1:1:1 because there's one of everything, so if C changes by +2, then A and B would change by -2. For the equation A + B -> 2C, the molar ratio is 1:1:2, so if C changes by +1, A and B would change by -0.5.

Simply add/subtract the change row from the initial row and you will be left with the mols of each chemical at equilibrium. Use the expression for Kp (check textbook) to create your Kp value from this.

Hope this helped!

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