Equilibrium Practice

At what time does the reaction reach equilibrium?

• t₁
• t₂
• t₃
• t₄

During equilibrium, the rates of the forward and the reverse reaction are ________

• the same 
• unequal
• unequal for exothermic reactions
• unequal for endothermic reactions

For the reaction...
SO₂ + O₂  <−>  SO₃
If the concentration of SO₂ is increased, the equilibrium of the reaction will shift ___________.

• left
• right
• left and right 
• neither left nor right

For the reaction...
SO₂ + O₂ <−>  SO₃
If the concentration of O₂ is decreased, the equilibrium of the reaction will shift ___________.

• left
• right
• left and right
• neither left nor right

For the reaction...
N_{2 (g)} +  3 H_2 (g) <−> 2 NH_{3 (g)}

If the pressure in the system is increased,  which substance will increase in concentration?

• N₂
• H₂
• N₂ and H₂
• NH₃

For the reaction...
heat  +  N₂  +  O₂  <−>  2NO
If the heat is added to the chemical system, the equilibrium will shift _______.

• left
• right
• left and right
• neither left nor right

For the reaction...
heat  +  N₂  +  O₂  <−>  2NO
If the heat is removed to the chemical system, the equilibrium will shift _______.

• left
• right
• both left and right
• neither left nor right

Given the K_c for a forward reaction, how can you find K_c for the reverse reaction?

• Divide K_c by 1

• Divide 1 by K_c

• Square K_c

• Take the square root of K_c

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