Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    1
    ReputationRep:
    Currently just finished studying equilibrium, and as revision id like to do some past equilibrium questions, even the most complex ones. So if any one has any questions at all, could you send me the link please thankya
    • Community Assistant
    • Study Helper
    Online

    15
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by miafrances19)
    Currently just finished studying equilibrium, and as revision id like to do some past equilibrium questions, even the most complex ones. So if any one has any questions at all, could you send me the link please thankya
    Q. When nitrogen gas and hydrogen gas are allowed to react in a closed container the following equilibrium is established.

    N2 (g) + 3H2 (g) <==> 2NH3 (g) .............. ΔH = –92.6 kJ

    (a) (i) Outline two characteristics of a reversible reaction in a state of dynamic equilibrium. [2]

    (ii) Predict, with a reason, how each of the following changes affects the position of equilibrium. [2]
    - The volume of the container is increased.
    - Ammonia is removed from the equilibrium mixture.

    (iii) Define the term activation energy, Ea. [1]

    (b) Ammonia is manufactured by the Haber process in which iron is used as a catalyst.
    Explain the effect of a catalyst on the rate of reaction. [2]

    (c) Typical conditions used in the Haber process are 500 °C and 200 atm, resulting in approximately 15 % yield of ammonia.
    (i) Explain why a temperature lower than 500 °C is not used. [2]

    (ii) Outline why a pressure higher than 200 atm is not often used. [1]

    (d) (i) Deduce the equilibrium constant expression, Kc, for the reaction shown above. [1]

    (ii) When 1.00 mol of nitrogen and 3.00 mol of hydrogen were allowed to reach equilibrium in a 1.00 dm3 container at a temperature of 500 °C and a pressure of 1000 atm, the equilibrium mixture contained 1.46 mol of ammonia. Calculate the value of Kc at 500 °C. [2]
    • Thread Starter
    Offline

    1
    ReputationRep:
    (Original post by charco)
    Q. When nitrogen gas and hydrogen gas are allowed to react in a closed container the following equilibrium is established.

    N2 (g) + 3H2 (g) <==> 2NH3 (g) .............. ΔH = –92.6 kJ

    (a) (i) Outline two characteristics of a reversible reaction in a state of dynamic equilibrium. [2]

    (ii) Predict, with a reason, how each of the following changes affects the position of equilibrium. [2]

    (iii) Define the term activation energy, Ea. [1]


    (b) Ammonia is manufactured by the Haber process in which iron is used as a catalyst.
    Explain the effect of a catalyst on the rate of reaction. [2]

    (c) Typical conditions used in the Haber process are 500 °C and 200 atm, resulting in approximately 15 % yield of ammonia.
    (i) Explain why a temperature lower than 500 °C is not used. [2]

    (ii) Outline why a pressure higher than 200 atm is not often used. [1]

    (d) (i) Deduce the equilibrium constant expression, Kc, for the reaction shown above. [1]

    (ii) When 1.00 mol of nitrogen and 3.00 mol of hydrogen were allowed to reach equilibrium in a 1.00 dm3 container at a temperature of 500 °C and a pressure of 1000 atm, the equilibrium mixture contained 1.46 mol of ammonia. Calculate the value of Kc at 500 °C. [2]
    Thank you sooooo much!
    Offline

    17
    ReputationRep:
    1 mol of N2 and 3 mol of H2 were mixed in a 1 dm3 container at 450 oC and allowed to come to equilibrium.

    1 mol of Ar was added to the container.

    Predict what effect this would have on the position of the equilibrium.
    • Thread Starter
    Offline

    1
    ReputationRep:
    (Original post by Pigster)
    1 mol of N2 and 3 mol of H2 were mixed in a 1 dm3 container at 450 oC and allowed to come to equilibrium.

    1 mol of Ar was added to the container.

    Predict what effect this would have on the position of the equilibrium.
    Im not sure D; would you be able to explain to me please??
    Offline

    17
    ReputationRep:
    It is almost a trick question.

    You're meant to think that adding Ar will increase the pressure and since there are more gas particles on the left, the equilibrium will shift to the right.

    But that doesn't happen. Why not?
    • Thread Starter
    Offline

    1
    ReputationRep:
    (Original post by Pigster)
    It is almost a trick question.

    You're meant to think that adding Ar will increase the pressure and since there are more gas particles on the left, the equilibrium will shift to the right.

    But that doesn't happen. Why not?
    Does Ar react with something to produce more gas particles?
    Offline

    17
    ReputationRep:
    Ar, like its Nobel gas friends are notoriously unreactive.
 
 
 
Poll
Do you agree with the PM's proposal to cut tuition fees for some courses?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.