Chem 220  CC #5        5 points            Name ___________________________lab______

Please put your answers in the blanks. Attach your work for questions 1,2,3, 4 and 5.

1.    2 HI  ó H₂   +  I₂    (all gases)   K = 0.018

If 1.0 mole of each HI, H₂ and I₂ are placed together into a 1.0 liter container, what will the equilibrium concentration of the H₂ be?

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2. What is the pH of  0.0100 M HA if the K_a equals 3.27 E-04 ?

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3.  N₂O₄  ó  2 NO₂    Exactly 1.0 mole N₂O₄ is placed in a 1.0 liter container and allowed to reach equilibrium. If the N₂O₄ is 20.0 % dissociated, what is the value of K?

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4. A 0.10 M HX solution has a pH= 4.0. What is the K_a ?

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5. What is the pH of a 0.10 M pyridine solution if K_b = 1.4 x 10^-9 ?

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6. The stronger the weak acid the _______________ (larger, smaller) the K_a.

7. The larger the pK_b , the _________________  (stronger, weaker) the weak acid.

8. As K_a increases the pH _________________ ( increases, decreases).

9. If K_a = 1.00 x 10^-5 for HZ, what does K_b of Z ^-1 equal? ________________

10. The conjugate acid of HSO₃ ^– is _____________________.