Equilibrium

This symbol indicates that a reaction is ____________

• reversible
• irreversible

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.

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

• to the left
• to the right
• to the left and right 
• neither left nor right

For the reaction...
SO₂ + O₂ <=>  SO₃
If the equilibrium position shifts to the right, the concentration of O₂ will ___________.

• increase
• decrease
• remain the same
• double

For the reaction...
N₂  +  O₂  <=>  2NO
If  O₂ is removed, the  concentration of N₂ will _______.

• increase
• decrease
• remain the same
• double

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

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

• N₂  (as 2 mol gas  → 4 mol gas)
• H₂ (as 2 mol gas  → 4 mol gas)
• N₂ and H₂ (as 2 mol gas  → 4 mol gas)
• NH₃ (as 4 mol gas  → 2 mol gas)

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]

Consider the following reaction:
2SO_2(g) + O_2(g) <=> 2SO_3(g):  ΔΗ = - 197 kJ mol ^-1
Which of the following will NOT shift the equilibrium position to the right?

• Adding more O₂
• Adding a catalyst
• increasing the pressure
• Lowering the temperature

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