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WorksheetsAcid Base Buffers AP Chem
Total questions: 24
Worksheet time: 39mins
Cu(s) + 2 Ag+ ↔ Cu2+ + 2 Ag(s)
If the equilibrium constant for the reaction above is 3.7 x 1015, which of the following correctly describes the standard voltage, E°, and the standard free energy change, ΔG°, for this reaction?
E° is positive and ΔG° is negative.
E° is negative and ΔG° is positive.
E° and ΔG° are both positive.
E° and ΔG° are both negative.
CuO(s) + H2(g) ↔ Cu(s) + H2O(g)
ΔH = –2.0 kilojoules mol–1
When the substances in the equation above are at equilibrium at pressure P and temperature T, the equilibrium can be shifted to favor the products by
increasing the pressure by means of a moving piston at constant T
increasing the pressure by adding an inert gas such as nitrogen
decreasing the temperature
adding a catalyst
For the reaction A(g) ↔ B(g) + C(g), the equilibrium constant, Kp, is 2 x 10–4 at 25 °C. A mixture of the three gases at 25 °C is placed in a reaction flask and the initial pressures are PA = 2 atmosphere, PB = 0.5 atmosphere, and PC = 1 atmosphere. At the instant of mixing, which of the following is true for the reaction as written?
ΔG < 0
ΔG > 0
ΔG° = 0
ΔG° < 0
In which of the following systems would the number of moles of the substances present at equilibrium NOT be shifted by a change in the volume of the system at constant temperature?
CO(g) + NO(g) ↔ CO2(g) + ½ N2(g)
N2(g) + 3 H2(g) ↔ 2 NH3(g)
N2(g) + 2 O2(g) ↔ 2 NO2(g)
NO(g) + O3(g) ↔ NO2(g) + O2(g)
Which of the following must be true for a reaction that proceeds spontaneously from initial standard state conditions?
ΔG° > 0 and Keq > 1
ΔG° > 0 and Keq < 1
ΔG° < 0 and Keq > 1
ΔG° < 0 and Keq < 1
H2C2O4 + 2 H2O ↔ 2 H3O+ + C2O4 2–
Oxalic acid, H2C2O4, is a diprotic acid with K1 = 5 x 10–2 and K2 = 5 x 10–5. Which of the following is equal to the equilibrium constant for the reaction represented above?
5 x 10–2
5 x 10–5
2.5 x 10–6
5 x 10–7
PCl3(g) + Cl2(g) ↔ PCl5(g) + energy
Some PCl3 and Cl2 are mixed in a container at 200°C and the system reaches equilibrium according to the equation above. Which of the following causes an increase in the number of moles of PCl5 present at equilibrium?
Decreasing the volume of the container
Raising the temperature
Adding a mole of He gas at constant volume
Raising the temperature and adding a mole of He gas at constant volume
4 HCl(g) + O2(g) ↔ 2 Cl2(g) + 2 H2O(g)
Equal numbers of moles of HCl and O2 in a closed system are allowed to reach equilibrium as represented by the equation above. Which of the following must be true at equilibrium?
The [HCl] must be less than [Cl2].
The [O2] must be greater than [HCl].
The [Cl2] must equal [H2O].
The [O2] must be greater than [HCl] and [Cl2] must equal [H2O].
2 SO2(g) + O2(g) ↔ 2 SO3(g) When 0.40 mole of SO2 and 0.60 mole of O2 are placed in an evacuated 1.00-liter flask, the reaction represented above occurs. After the reactants and the product reach equilibrium and the initial temperature is restored, the flask is found to contain 0.30 mole of SO3. Based on these results, the expression for the equilibrium constant, Kc, of the reaction is
2 SO3 (g) ↔ 2 SO2 (g) + O2 (g)
After the equilibrium represented above is established, some pure O2 (g) is injected into the reaction vessel at constant temperature. After equilibrium is reestablished, which of the following has a lower value compared to its value at the original equilibrium?
Keq for the reaction.
The total pressure in the reaction vessel.
The amount of SO3 (g) in the reaction vessel.
The amount of SO2 (g) in the reaction vessel.
W(g) + X(g) ↔ Y(g) + Z(g)
Gases W and X react in a closed, rigid vessel to form gases Y and Z according to the equation above. The initial pressure of W(g) is 1.20 atm and that of X(g) is 1.60 atm. No Y(g) or Z(g) is initially present. The experiment is carried out at constant temperature. What is the partial pressure of Z(g) when the partial pressure of W(g) has decreased to 1.0 atm?
0.20 atm
0.40 atm
1.0 atm
1.2 atm
2 NO(g) + O2(g) ↔ 2 NO2(g)
ΔH < 0
Which of the following changes alone would cause a decrease in the value of Keq for the reaction represented above?
Decreasing the temperature
Increasing the temperature
Decreasing the volume of the reaction vessel
Adding a catalyst
Which solution A and B of equal volume and concentration mixed together to form a buffer?
Hydrochloric acid and potassium chloride
Nitric acid and potassium nitrate
Acetic acid and potassium hydroxide
Sulfurous acid and potassium sulfite
When making a buffer of pH = 5, acids with the following Ka values are available. Which would be the best acid to use?
1.8 x 10-5
1.8 x 10-8
4.9 x 10-10
3.0 x 10-8
A buffer has a pH of 4.85 and contains formic acid and potassium formate. What can you conclude about the concentrations of the components of the buffer? The Ka of formic acid is 1.8 x 10-4.
Formic acid > Potassium formate
Formic acid < Potassium formate
Formic acid = Potassium formate
More information is needed to determine the relative concentrations
