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Worksheet: Predicting Concentration Changes from Reaction Quotients

Q1:

One of the solubility rules is that all chlorides are soluble except H g C l 2 2 , A g C l , P b C l 2 , and C u C l .

Which of the following expressions correctly describes the equilibrium constant, 𝐾 c , for the equilibrium

  • A 𝐾 β‰ˆ 1 c
  • B 𝐾 ≫ 1 c
  • C 𝐾 β‰ͺ 0 c
  • D 0 < 𝐾 β‰ͺ 1 c
  • E 𝐾 = 0 c

Q2:

For the reaction 2 S O ( ) 2 S O ( ) + O ( ) 3 2 2 g g g , where 𝐾 = 1 6 . 5 P , P( S O 3 ) = 1.00 atm, P( S O 2 ) = 1.00 atm, and P( O 2 ) = 1.00 atm:

What is the reaction quotient?

  • A 𝑄 = 1 . 5 0 P
  • B 𝑄 = 2 . 0 0 P
  • C 𝑄 = 0 . 5 0 P
  • D 𝑄 = 1 . 0 0 P
  • E 𝑄 = 2 . 5 0 P

In which direction will the reaction proceed from this point?

  • ATo the right
  • BNeither: it has reached equilibrium
  • CTo the left

Q3:

The initial concentrations of the species in a solution are as follows: [ C O ] = 0.0094 M, [ H O ] 2 = 0.0025 M, [ C O ] 2 = 0.0015 M, and [ H ] 2 = 0.0076 M. These species participate in a reversible reaction represented by the equation: In which direction does the reaction shift in order to reach equilibrium?

  • ANeither: the reaction is already at equilibrium.
  • BTo the left
  • CTo the right

Q4:

Benzene is one of the compounds used as octane enhancers in unleaded gasoline. It is manufactured by the catalytic conversion of acetylene to benzene:

Which value of 𝐾 c would make this reaction most useful commercially?

  • A 𝐾 β‰ˆ 0 . 1 c
  • B 𝐾 β‰ˆ 1 c
  • C 𝐾 β‰ˆ 0 c
  • D 𝐾 β‰ˆ 1 0 c
  • E 𝐾 β‰ˆ 0 . 0 1 c

Q5:

For the reaction N ( ) + O ( ) 2 N O ( ) 2 2 g g g , where 𝐾 = 0 . 0 5 0 P , 𝑃 ( N O ) = 10.0 atm, and 𝑃 ( N ) 2 = 𝑃 ( O ) 2 = 5 atm.

What is the reaction quotient?

  • A 𝑄 = 0 . 4 P
  • B 𝑄 = 0 . 2 5 P
  • C 𝑄 = 2 . 5 P
  • D 𝑄 = 4 . 0 P

In which direction will the reaction proceed from this point?

  • ATo the left
  • BNeither: it has reached equilibrium
  • CTo the right

Q6:

The following reaction has 𝐾 = 4 . 5 0 Γ— 1 0 P βˆ’ 5 at 720 K:

If, at this temperature, a reaction vessel is filled with each gas to the partial pressures listed, in which direction will it shift to reach equilibrium? 𝑃 ( N H ) 3 = 93 atm, 𝑃 ( N ) 2 = 48 atm, and 𝑃 ( H ) 2 = 52 atm.

  • ANeither: it has reached equilibrium
  • BTo the right
  • CTo the left

Q7:

For the reaction 2 N H ( ) N ( ) + 3 H ( ) 3 2 2 g g g , 𝐾 = 6 . 8 Γ— 1 0 P οŠͺ , 𝑃 ( N H ) 3 = 3.0 atm, 𝑃 ( N ) 2 = 2.0 atm, and 𝑃 ( H ) 2 = 1.0 atm.

If the partial pressures of all species are 1.0 atm under standard conditions, what is the reaction quotient for this reaction?

  • A 𝑄 = 4 . 5 P
  • B 𝑄 = 0 . 6 7 P
  • C 𝑄 = 1 8 P
  • D 𝑄 = 0 . 2 2 P
  • E 𝑄 = 0 . 8 9 P

In which direction will the reaction proceed from this point?

  • ATo the right
  • BNeither: it has reached equilibrium
  • CTo the left

Q8:

An equilibrium is established according to the following equation:

What will happen in a solution that is 0.20 M each in H g 2 2 + , N O 3 – , H + , H g 2 + , and H N O 2 ?

  • A H g 2 2 + will be reduced and N O 3 – oxidized.
  • B H g 2 2 + will be oxidized and N O 3 – reduced.
  • C H g 2 + will be oxidized and H N O 2 reduced.
  • D H g 2 + will be reduced and H N O 2 oxidized.
  • EThere will be no change because all reactants and products have an activity of 1.

Q9:

The initial concentrations of the species in a solution are as follows: [ C O ] = 0.011 M, [ H O ] 2 = 0.0011 M, [ C O ] 2 = 0.037 M, and [ H ] 2 = 0.046 M. These species participate in a reversible reaction represented by the equation: In which direction does the reaction shift in order to reach equilibrium?

  • ANeither: the reaction is already at equilibrium.
  • BTo the right
  • CTo the left

Q10:

One of the solubility rules is that all chlorides are soluble except H g C l 2 2 , A g C l , P b C l 2 , and C u C l .

Which of the following expressions correctly describes the equilibrium constant, 𝐾 c , for the equilibrium

  • A 0 < 𝐾 β‰ͺ 1 c
  • B 𝐾 β‰ˆ 1 c
  • C 𝐾 β‰ͺ 0 c
  • D 𝐾 ≫ 1 c
  • E 𝐾 = 0 c

Q11:

For the reaction 2 N O ( ) + C l ( ) 2 N O C l ( ) g g g 2 , where 𝐾 = 4 . 6 Γ— 1 0 c 4 , [ N O ] = 1.00 M, [ C l ] 2 = 1.00 M, and [ N O C l ] = 0 M:

What is the reaction quotient?

  • A 𝑄 = 1 . 0 0 c
  • B 𝑄 c undefined
  • C 𝑄 = 2 . 0 0 c
  • D 𝑄 = 0 c
  • E 𝑄 = 0 . 5 0 c

In which direction will the reaction proceed from this point?

  • ATo the right
  • BNeither: it has reached equilibrium
  • CTo the left

Q12:

For the reaction initial concentrations of the species are:

  • [ C O ] = 0.0203 M,
  • [ H O ] 2 = 0.0203 M,
  • [ C O ] 2 = 0.0040 M,
  • [ H ] 2 = 0.0040 M.

In which direction does the reaction shift in order to reach equilibrium?

  • ANeither: the reaction is already at equilibrium.
  • BTo the left
  • CTo the right

Q13:

For the reaction 2 N H ( ) N ( ) + 3 H ( ) 3 2 2 g g g , 𝐾 = 1 7 c , [ N H ] 3 = 0.20 M, [ N ] 2 = 1.00 M, and [ H ] 2 = 1.00 M.

If the concentrations of all species are 1.00 M under standard conditions, what is the reaction quotient for this reaction?

  • A 𝑄 = 0 . 2 0 c
  • B 𝑄 = 5 . 0 c
  • C 𝑄 = 0 . 0 4 0 c
  • D 𝑄 = 2 5 c
  • E 𝑄 = 0 . 4 5 c

In which direction will the reaction proceed from this point?

  • ATo the left
  • BNeither: it has reached equilibrium
  • CTo the right

Q14:

Sulfuryl chloride decomposes reversibly into chlorine and sulfur dioxide, as shown by the equation:

I n o n e g a s m i x t u r e , [ S O C l ] 2 2 = 0.16 M, [ C l ] 2 = 0.13 M and [ S O ] 2 = 0.075 M. The value of 𝐾 c for the reaction is 0.078. In which direction will the reaction shift in order to reach equilibrium?

  • ANeither: it has already reached equilibrium.
  • BTo the left
  • CTo the right