# Equilibria 2 (Worksheets)


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Work in groups on these problems. You should try to answer the questions without referring to your textbook. If you get stuck, try asking another group for help.

1. Write the equilibrium expression for each of the following: Where possible, express both $$K_c$$ and $$K_p$$.

 a) $$2NaN_{3\,(s)} \rightleftharpoons 2Na_{(s)} + 3N_{2\,(g)}$$ b) $$4NH_{3\,(g)} + 5O_{2\,(g)} \rightleftharpoons 4NO_{(g)} + 6H_2O_{(g)}$$ c) $$2HCl_{(aq)} + Ca(OH)_{2\,(aq)} \rightleftharpoons 2H_2O_{(l)} + CaCl_{2\,(aq)}$$

2. For equation 1b, would $$K_c = K_p$$? Explain.

3. Determine the equilibrium concentrations for each species in the equation:

 $$H_{2\,(g)} + I_{2\,(g)} \rightleftharpoons 2HI_{(g)}$$

if the initial concentrations of $$H_2$$ and $$I_2$$ are 1.0 M and $$K_c$$ = 54.3 at 430oC.

4. Given the reaction above:
If the initial concentrations of $$H_2$$ and $$I_2$$ are 1.0 M and the initial concentration of $$HI$$ is 0.5 M ($$K_c$$ = 54. 3 at 430oC), is the reaction at equilibrium? If not, which way will the reaction proceed?

5. According to Le Chatelier's Principle,

a) what effect would the addition of $$Cl^-$$ have on the equilibrium below?

 $$CoCl_2 + 2Cl^- \rightleftharpoons CoCl_4^{2-}$$

b) what effect would the addition of $$Ag^+$$ have on the equilibrium in problem 5a if the $$Ag^+$$ precipitates as $$AgCl$$?