Chem 2 final

Which of the following statements is TRUE?

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  Reaction quotient is the concentration of the reactants raised to the stoichiometric coefficients divided by the concentration of the products raised to their stoichiometric coefficients, measured at any point in the reaction.

  
  

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  Reaction quotient is the concentration of the reactants raised to the stoichiometric coefficients divided by the concentration of the products raised to their stoichiometric coefficients, measured at equilibrium.

  
  

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  Reaction quotient is the concentration of the products raised to the stoichiometric coefficients divided by the concentration of the reactants raised to their stoichiometric coefficients, measured at equilibrium.

  
  

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  Reaction quotient is the concentration of the products raised to the stoichiometric coefficients divided by the concentration of the reactants raised to their stoichiometric coefficients, at the point both are equal.

  
  

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  Reaction quotient is the concentration of the products raised to the stoichiometric coefficients divided by the concentration of the reactants raised to their stoichiometric coefficients, measured at any point in the reaction.

  
  

Define Le Chatelier's Principle.

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  When a chemical system at equilibrium is disturbed, the system shifts in a direction that maximizes the disturbance.

  
  

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  A system will always change if the volume changes.

  
  

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  When a chemical system at equilibrium is disturbed, the system shifts in a direction that equals the disturbance.

  
  

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  When a chemical system at equilibrium is disturbed, the system shifts in a direction that minimizes the disturbance.

  
  

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  A system will always change if the pressure changes.

  
  

Consider the following reaction at equilibrium. What will happen if Fe₂O₃ is added to the reaction?

4 FeS₂(s) + 11 O₂(g) ⇌ 2 Fe₂O₃(s) + 8 SO₂(g)

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  The equilibrium will change in the direction of the reactants.

  
  

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  The equilibrium constant will decrease.

  
  

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  The equilibrium constant will increase.

  
  

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  No change in equilibrium is observed.

  
  

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  The equilibrium will change in the direction of the products.

  
  

Which of the following statements is TRUE?

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  None of the above are true.

  
  

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  If Q > K, it means the forward reaction will proceed to form more products.

  
  

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  All of the above are true.

  
  

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  If Q = K, it means the reaction is at equilibrium.

  
  

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  If Q < K, it means the reverse reaction will proceed to form more reactants.

  
  

Consider the following reaction, equilibrium concentrations, and equilibrium constant at a particular temperature. Determine the equilibrium concentration of NO₂(g).

N₂O₄(g) ⇌ 2 NO₂(g) K_c = 0.21

[N₂O₄]_eq = 0.033 M

• 6.9 × 10^-3 M

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  8.3 × 10^-2 M

  
  

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  12 × 10^-2 M

  
  

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  144 M

  
  

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  1.44 M

  
  

Phosphorous trichloride and phosphorous pentachloride equilibrate in the presence of molecular chlorine according to the reaction:

PCl₃(g) + Cl₂(g) ⇌ PCl₅(g)

An equilibrium mixture at 450 K contains
P_PCl3 = 0.124 atm,
P_Cl2 = 0.157 atm, and
P_PCl5 = 1.30 atm. What is the value of K_p at this temperature?

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  1.50 × 10^-2

  
  

• 66.7

• 4.63

• 1.02

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  2.53 × 10^-2

  
  

At a certain temperature, K_c equals 1.4 × 10² for the reaction:

2 CO(g) + O₂(g) ⇌ 2 CO₂(g).

If a 3.00-L flask contains 0.400 mol of CO₂ and 0.100 mol of O₂ at equilibrium, how many moles of CO are also present in the flask?

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  0.107 mol

  
  

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  0.555 mol

  
  

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  0.185 mol

  
  

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  0.0114 mol

  
  

Consider the following reaction and its equilibrium constant:

4 CuO(s) + CH₄(g) ⇌ CO₂(g) + 4 Cu(s) + 2 H₂O(g) K_c = 1.10

A reaction mixture contains 0.20 M CH₄, 0.70 M CO₂ and 1.5 M H₂O. Which of the following statements is TRUE concerning this system?

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  The reaction will shift in the direction of products.

  
  

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  The equilibrium constant will increase.

  
  

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  The reaction will shift in the direction of reactants.

  
  

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  The system is at equilibrium.

  
  

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  The reaction quotient will increase.

  
  

What is the conjugate base of H₂PO₄⁻ ?

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  HPO₄^2-

  
  

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  H₃PO₄

  
  

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  H₃O⁺

  
  

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  OH⁻

  
  

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  PO₄^3-

  
  

Which of the following species is amphoteric?

• HF

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  HPO₄^2-

  
  

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  SO₄^2-

  
  

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  NH₄⁺

  
  

• LiI