AP Chemistry - Equilibrium
1. At a certain temperature the value of Kp for the following reaction
N2(g) + O2(g) <===> 2 NO(g)
is 4.0 x 10- 4. If at some time the partial pressures are PN2 = 0.50 atm, PO2 = 0.25 atm, and PNO = 4.2 x10- 3 atm, is the system at equilibrium and if not in what direction will it run?
2. The equilibrium constant for the following reaction
H2(g) + I2(g) <===> 2 HI(g)
is 15.77. If 1.00 moles of H2 and 1.00 moles of I2 are placed into a 0.500 L flask what will the equilibrium concentrations be?
3. Given the reaction NH4NO3(s) <===> NH4+ + NO3-ΔH = 26.2 kJ/mol,
what effect will raising the temperature have on the concentration of ammonium ion?
4. At 400oC, the Keq for the Haber process
3 H2(g) + N2(g) <==> 2 NH3(g)
is 1.7 x 10- 4. If a 1 liter flask starts with 2 moles of ammonia and 1 mole of hydrogen, what will the equilibrium concentrations be?
5. What is the [OH- ] in a saturated solution of Ca(OH)2? (Ksp = 7.9 x 10-6)
6. What is the maximum concentration of sulfate that can be found in a 0.01 M solution of barium nitrate without barium sulfate precipitating? Assume the nitrate salt is completely soluble. Ksp of barium sulfate = 1.1 x 10-10.
7. A chemist has a solution that is 0.02 M Cu+2 and 0.20 M Zn+2. If the solution is made 1.00 M H+, and H2S(g) is bubbled in until it is saturated, what, if anything, will precipitate?
Ksp of CuS = 8 x 10-37 K for H2S <==> 2 H+ + S-2 = 1 x 10-22
Ksp of ZnS = 1 x 10-22
8. The Haber process, which involves reacting hydrogen and nitrogen together at high temperatures, is the most common method of production of ammonia in this country. (See #4 if you don't remember the equation). Heating this reaction causes the equilibrium to shift towards the reactant side of the equation. Why then, if the goal is to produce ammonia, is this reaction run at high temperatures? Also, suggest a way that a higher yield can be produced at this high temperature. (This is the kind of question that calls on you to remember things from the past!)