18.2 Equilibrium and Constant Warm-Up

Which is the reactant - and why?

• A, as concentration decreases
• B, as concentration decreases
• A, as concentration increases
• B, as concentration increases

At what time the reaction reached equilibrium?

• t₁
• t₂
• t₃
• t₄

What is the equation/reaction for this Kc expression?

• O₃ ⇌ 3O₂

• 2O₃ ⇌ 3O₂

• 2O₃ ⇌ O₂

• 3O₂ ⇌ 2O₃

Consider the following equation 
H_{2 (g)} + I_{2 (g)} <===> 2 HI_(g)  
Calculate Keq if at 300^oK the concentrations are [H₂] = 0.40 M   [I₂] = 0.45 M ; [HI] = 0.30 M

• 0.42
• 0.5
• 1.67
• 0.6

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

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]