Problems On Equilibrium

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Remember: Need to Write Down First Balanced Chemical Reaction and Equilibrium Constant Expression

1. At 750degC, the following reaction reaches equilibrium in a 1-L container.
1 H_2(g) + 1 CO_2(g) <--> 1 H₂O_(g) + 1 CO_(g)
At equilibrium, the 1-L flask contains 0.053moles hydrogen, 0.053moles carbon dioxide, 0.047moles water, and 0.047moles carbon monoxide. Calculate K_eq for this reaction.

2.For the reaction , 2 H₂S_(g) <--> 2 H_2(g) + S_2(g)
K_eq = 2.3E-4. If the equilibrium concentration of H₂S and H₂ are 0.15M and 0.010M, what is the equilibrium concentration of S₂?

3. For reaction 2 SO_2(g) + O_2(g) <--> 2 SO_3(g)
a 0.25-L container initially has 2.00 moles of SO₃. If 75% of this compound has reacted at equilibrium, what are the equilibrium concentration of all species and then calculated K (equilibrium constant)?

4. The reaction PCl_5(g) <---> PCl_3(g) + Cl_2(g) has a K= 11.5. A 0.5-L gas vessel has one mole of PCl₅, what is the equilibrium concentration of all species?For 2007-2008, do not do this question, Question 4, only for extra credit. It is an Ice Box Problem.

Answer:
1. K = 0.786 , no units
2. [S₂] = 5.18E-2 M
3. [SO₂] = 6.00M, [SO₃] = 2.00M , [O₂] = 3.00M and K = 3.70E-2, units = M^-1
4. [PCl₃] = 1.74M, [PCl₅] = 0.265M , [Cl₂] = 1.74M