AP Chem Unit 8 Review

At equilibrium the concentration of all species in the reaction is _________.

• Constant
• Increasing
• Decreasing
• Oscillating

Tags

NGSS.HS-PS1-6

NGSS.HS-PS1-7

Increasing the temperature on a ________ reaction will increase the concentration of products.

• Endothermic
• Exothermic
• Isothermic

Tags

NGSS.HS-PS1-5

Silver chromate, Ag₂CrO₄, has a Ksp of 4.0 x 10^-12. What is the concentration of silver ions in a saturated solution.

• 2.0 x 10^-4 M

• 1.0 x 10^-4 M

• 2.0 x 10^-12 M

• 1.0 x 10^-12 M

When the chemical reaction A + B ↔ C+ D is at equilibrium,

• both the forward and reverse reactions have stopped.
• the sum of the concentrations of A and B equals the sum of the concentrations of C and D.
• all four concentrations are equal.
• neither the forward nor the reverse reactions have stopped.

Tags

NGSS.HS-PS1-6

H₂(g) + I₂(g) ⇄ 2 HI(g)

At 450^oC, 2.0 moles each of H₂(g), I₂(g), and HI(g) are combined in a 1.0 L rigid container. The value of K_c at 450^oC is 50. Which of the following will occur as the system moves toward equilibrium?

• More H₂(g) and I₂(g) will form because Q<K.

• More HI(g) will form because Q<K

• More HI will form because Q>K

• No net reaction will occur, because the number of molecules is the same on both sides of the equation.

Tags

NGSS.HS-PS1-5

PCl₃(g) + Cl₂(g) ⇄ PCl₅(g) K_c = 1.5

At a certain point in time, a 1.00 L rigid reaction vessel contains 1.5 mol of PCl₃(g), 1.0 mol of Cl₂(g), and 3.0 mol of PCl₅(g). Which of the following statements is true?

• The equilibrium will shift to the right since there are less moles from the equation.

• The pressure of PCl₃ will increase because Q > K_c.

• The pressure of PCl₃ will decrease because Q < K_c.

• The pressure will decrease because Q > K_c.

Tags

NGSS.HS-PS1-7

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 K_eq > 1

• ΔG° > 0 and K_eq < 1

• ΔG° < 0 and K_eq > 1

• ΔG° < 0 and K_eq < 1

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.

Tags

NGSS.HS-PS1-6