5. Which side of the equilibrium will the following reactions most like sit? Give a thorough explanation for how you derived your answers. The cations are omitted for clarity. C points) + HO + H₂O OH

Because carbonic acid undergoes a second ionization, the student in Exercise 12.39 is concerned that the hydrogen ion concentration she calculated is not correct. She looks up the equilibrium constant for the reaction HCO,-(aq) «=* H+(aq) + COf'(aq) Upon finding that the equilibrium constant for this reaction is 4.8 X 10“H, she decides that her answer in Exercise 12.39 is correct. Explain her reasoning. A student is simulating the carbonic acid—hydrogen carbonate equilibrium in a lake: H,CO,(aq) 5=6 H+(aq) + HCO,'(aq) K = 4.4 X 10'7She starts with 0.1000 A1 carbonic acid. W hat are the concentrations of all species at equilibrium?

7-17 If a certain reaction takes 16 h to go to completion at 10°C, what temperature should we run it if we want it to go to completion in 1 h?

How is the strength of an acid related to the position of its ionization equilibrium? Write the equations for the dissociation (ionization) of HCI, HNO3, and HClO4in water. Since all these acids are strong acids, what does this indicate about the basicity of the Cl-, NO3, and ClO4ions? Are aqueous solutions of NaCl, NaNO3, or NaClO4basic?

If you observe the following reaction at equilibrium, is it possible to tell whether the reaction stated with pure NO2 or with pure N2O4? 2NO2(g)N2O4(g)

7-22 If you add a piece of marble, CaCO3 to a 6 M HCI solution at room temperature, you will see some bubbles form around the marble as gas slowly rises. If you crush another piece of marble and add it to the same solution at the same temperature, you will see vigorous gas formation, so much so that the solution appears to be boiling. Explain.

Based on the diagrams, chemical reaction, and reaction conditions depicted in Problem 9-83, which of the diagrams represents the equilibrium mixture if the numerical value of the equilibrium constant is 9.0?

7-29 The following reaction was allowed to reach equilibrium at 25°C. Under each component is its equilibrium concentration. Calculate the equilibrium constant, K, for this reaction.

. Explain what it means that a reaction has reached a state of chemical equilibrium. Explain why equilibrium is a dynamic state: Does a reaction really “stop” when the system reaches a state of equilibrium? Explain why, once a chemical system has reached equilibrium, the concentrations of all reactants remain constant with time. Why does this constancy of concentration not contradict our picture of equilibrium as being dynamic? What happens to the rates of the forward and reverse reactions as a system proceeds to equilibrium from a starting point where only reactants are present?

7-31 Here are equilibrium constants for several reactions. Which of them favor the formation of products, and which favor the formation of reactants? (a) (b) 32 (c) 4.5 (d) (e) 0.0032