equilibrium reading guide quiz

When the system X + 2 Y <=> Z has reached equilibrium, which of the following is TRUE?

• Forward reaction and Backward reaction stop.
• Forward reaction has sped up and backward reaction has slowed down.
• Forward and backward reactions occur at the same rate.
• Forward reaction has slowed down and backward reaction has sped up.

What is the K_c expression for this reaction?
   2 NO_(g)  +  O_2(g) ⇌  2 NO_2(g)

• K_c = [NO₂]² / [NO]² [O₂]
• K_c =  [NO]² [O₂] / [NO₂]²
• K_c = [NO]² [O₂] [NO₂]²
• K_c = [NO₂]² / [NO]² +  [O₂]

An equilibrium constant with a large value, e.g. K_c = 1000, indicates…

• A very fast reaction
• Mostly products at equilibrium
• Mostly reactants at equilibrium
• Nothing useful at all

Le Chatelier's Principle states that.... 
If a (dynamic) equilibrium is disturbed by changing the conditions, the position of equilibrium................

• moves to increase the change
• moves to counteract the change
• does not change

Changes in pressure will only affect substances that are in the __________ state.

• gaseous
• liquid
• solid

What are [A] and [B]?

• concentration of reactants
• concentration of products
• energy of reactants
• energy of products

In an exothermic reaction energy is transferred from

• reactants to their surroundings
• the surroundings to reactants
• one reactant to another
• the container to the chemicals

What is the equilibrium expression for:
Fe₃O₄(s) + 4H₂(g) <=> 3Fe(s) + 4H₂O(g)
K_c =

• [Fe]³ [H₂O]⁴  / [Fe₃O₄] [H₂]⁴
• [Fe₃O₄] [H₂]⁴ /  [Fe]³ [H₂O]⁴
• [H₂O]⁴ / [H₂]⁴
• [Fe] [H₂O] / [Fe₃O₄] [H₂]

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 mol L^-1 SO₃ , and 0.30 mol L^-1 NO,
0.15 mol L^-1NO₂ , and 0.20 mol L^-1 SO₂.
Calculate the equilibrium constant  for this reaction. 

• 4
• .42
• .25
• 1

What are the two factors to look for when determining if the reaction is at equilibrium?

• Forward reaction rate is faster than the reverse and concentrations are equal

• Forward and reverse reaction rates are equal and concentration is constant

• Forward and reverse reaction rates are equal and concentration is equal

• Forward reaction rate is faster than the reverse and concentration is equal