CHM 112 Chapter 14 Quiz

Define chemical equilibrium.

• A reaction is reversible.
• The concentration of the reactants is equal to the concentration of the products.
• The rate of a forward reaction is equal to the rate of the reverse reaction.
• The reaction stops and no further change in concentration occurs.

Tags

NGSS.HS-PS1-6

The following reaction is investigated (assume an ideal gas mixture):

2N₂O(g) + N₂H₄(g) ↔ 3N₂(g) + 2H₂O(g)

Initially there are 0.100 mol of N₂O and 0.25 mol of N₂H₄, in a 10.0-L container. If there are 0.059 mol of N₂O at equilibrium, how many moles of N₂ are present at equilibrium?

• 0.021

• 0.042

• 0.062

• 0.12

At elevated temperatures ammonium carbonate, NH₂COONH₄, is in equilibrium with NH₃ and CO₂ according to the equation;

NH₂COONH₄(s) ↔ 2 NH₃(g) + CO₂(g)

What is the equilibrium expression for this reaction?

• K = 2 [NH₃][CO₂]

  [NH₂COONH₄]

• K = [NH₃]²[CO₂]

  [NH₂COONH₄]

• K = 2 [NH₃][CO₂]

• K = [NH₃]²[CO₂]

Tags

NGSS.HS-PS1-6

A large value of K_c indicates--

• more products than reactants at equilibrium

• more reactants than products at equlibrium

• reactants = products

• only products are present at equilibrium

Consider the following reaction :    
SO_{2 (g)} +  NO_{2 (g)} ↔ SO_{3 (g)} + NO (g)  
had reached a state of equilibrium, was found to contain   0.40 M SO₃ , 0.30 M NO, 0.15 M NO₂ , and 0.20 M SO₂. Calculate the equilibrium constant  for this reaction.

• 4
• .42
• .25
• 1

Tags

NGSS.HS-PS1-6

For the reaction 2H₂S(g) --> 2H₂(g) + S₂(g), K_c = 9.1 × 10² at 750 K. What will happen when 0.10 mol of H₂S, 1.0 mol of H₂, and 1.5 mol of S₂ are added to a 1.0-L container and the system is brought to 750 K?

• Q>K, reaction will shift towards reactants

• Q = K, so reaction is at equilibrium- nothing will happen

• Q < K, reaction will shift towards products

Tags

NGSS.HS-PS1-5

Given the equilibrium constants for the equilibria,

2NH₄⁺(aq) + 2H₂O(l) <--> 2NH₃(aq) + 2H₃O⁺(aq); K_c = 3.24x10^-19

CH₃COOH(aq) + H₂O(l) <--> CH₃COO^-(aq) + H₃O⁺(aq); K_c = 1.75x10^-5

determine K_c for the following equilibrium.

CH₃COOH(aq) + NH₃(aq) <--> CH₃COO^-(aq) + NH₄⁺(aq)

• 3.07x10⁴

• 3.25x10^-5

• 9.96x10^-15

• 2.98x10⁶

In an experiment, 0.30 mol H₂ and 0.30 mol I₂ are initially mixed in a 1.00-L container, and the reaction forms HI. If K_c = 49. for this reaction, what is the equilibrium concentration of HI?

I₂(g) + H₂(g) ↔2HI(g)

• 0.58 M

• 0.53 M

• 0.47 M

• 0.040 M

For a given reaction, N₂ + 3H₂ --> 2NH₃. 1.0 M of N₂ is added to 2.0 M H₂. Once equilibrium has been established, it is found the molarity of NH₃ is 0.25M. What is the equilibrium concentration of N₂ and H₂?

• [N₂] = 0.875 M, [H₂ ]= 1.625

• [N₂] = 0.85 M, [H₂ ]= 0.75

• [N₂] = 0.75 M, [H₂ ]= 1.875

• [N₂] = 0.5 M, [H₂ ]= 0.125

Tags

NGSS.HS-PS1-7

2NH₃+22kJ↔N₂+3H₂
Which direction does the reaction shift if NH₃ was added?

• Shift right 
• Shift left
• No shift
• Shift both directions

Tags

NGSS.HS-PS1-5