AP Chem Topics 7.1 - 7.10

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

Identify the incorrect statement about achieving equilibrium.

• achieved when product and reactant concentrations are equal

• achieved when forward and reverse reaction rates are same

• achieved when concentration of reactants is stable/constant

• achieved when concentration ratio of reactants to products becomes stable, thus fixing the equilibrium constant (equilibrium position)

Tags

NGSS.HS-PS1-6

At what time did the reaction reach equilibrium?

• t₁

• t₂

• t₃

• t₄

Identify the labels (a) and (b) on the graph.

• a is concentration of reactants and b is the concentration of product
• a is concentration of product and b is the concentration of reactant
• a is the volume of reactants and b is the volume of product
• a the mass of reactants and b is the mass of product

Tags

NGSS.HS-PS1-5

NGSS.HS-PS1-6

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]

Tags

NGSS.HS-PS1-7

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

Tags

NGSS.HS-PS1-6

Given: 2A(g) <=> 2B(g) + C(g). At a particular temperature, K_c = 16000.
Raising the pressure, by decreasing the volume of the container, will...

• cause the value of K_c to increase
• cause the value of K_c to decrease
• have no effect on the value of K_c as temperature does not change
• favour the forward reaction

Tags

NGSS.HS-PS1-6

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

Tags

NGSS.HS-PS1-6

NGSS.HS-PS1-7

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]

5.00 mol of H₂ and 5.00 mol of I₂ are added to a 5.00 L container. If the value for K_c for the reaction is 4.00 x 10², what are the equilibrium concentrations for each species?

H_{2 (g)} + I_{2 (g)} --> 2 HI _(g)

• [H₂] = 1.515 [I₂ ] = 1.515 [HI] = 3.03

• [H₂] = 0.101 [I₂ ] = 0.101 [HI] = 1.81

• [H₂] = 0.151 [I₂ ] = 0.151 [HI] = 0.302

• [H₂] = 1.515 [I₂ ] = 1.515 [HI] = 0.302