JAMB Chemistry questions: Chemical equilibrium

21 questions with answers and explanations. Tap an option to check yourself.

1. Question 1· Chemical equilibrium· JAMB

   Adding a catalyst to a reaction at equilibrium

   • Amakes equilibrium reached faster without changing its position
   • Bincreases the yield of products
   • Cshifts the equilibrium to the left
   • Dchanges the value of the equilibrium constant

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2. Question 2· Chemical equilibrium· JAMB

   For H₂(g) + I₂(g) ⇌ 2HI(g), increasing the pressure

   • Adoubles the yield of HI
   • Bshifts the equilibrium to the right
   • Cshifts the equilibrium to the left
   • Dhas no effect on the position of equilibrium

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3. Question 3· Chemical equilibrium· JAMB

   For the equilibrium N₂ + 3H₂ ⇌ 2NH₃ (ΔH negative), the yield of ammonia is increased by:

   • Araising the temperature
   • Blowering the pressure
   • Craising the pressure
   • Dremoving nitrogen

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4. Question 4· Chemical equilibrium· JAMB

   A reversible reaction is at equilibrium when

   • Athe rates of the forward and backward reactions are equal
   • Ball the reactants have been used up
   • Cthe reaction has stopped completely
   • Dthe products equal the reactants in mass

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5. Question 5· Chemical equilibrium· JAMB

   For a reversible reaction whose forward reaction is exothermic, lowering the temperature

   • Ahas no effect
   • Bfavours the backward reaction
   • Cfavours the forward reaction and increases the yield of products
   • Dstops the reaction

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6. Question 6· Chemical equilibrium· JAMB

   The value of the equilibrium constant of a reaction is changed only by a change in

   • Aconcentration
   • Bpressure
   • Ctemperature
   • Dthe presence of a catalyst

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7. Question 7· Chemical equilibrium· JAMB

   Removing a product from an equilibrium mixture

   • Ashifts it towards the reactants
   • Bshifts the equilibrium towards the products
   • Chas no effect
   • Dstops the reaction

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8. Question 8· Chemical equilibrium· JAMB

   For 2SO₂(g) + O₂(g) ⇌ 2SO₃(g), ΔH is negative. Raising the temperature will

   • Ashift the equilibrium to the left and reduce the yield of SO₃
   • Bshift the equilibrium to the right
   • Chave no effect on the equilibrium
   • Dincrease the yield of SO₃

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9. Question 9· Chemical equilibrium· JAMB

   Adding more reactant to a system at equilibrium shifts the equilibrium

   • Ain an unpredictable way
   • Btowards the reactants
   • Cnowhere
   • Dtowards the products

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10. Question 10· Chemical equilibrium· JAMB

    The typical conditions used in the Haber process are

    • Aabout 450 °C, about 200 atm and an iron catalyst
    • B25 °C, 1 atm and no catalyst
    • C1000 °C, 1 atm and platinum
    • D100 °C, 1000 atm and nickel

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11. Question 11· Chemical equilibrium· JAMB

    Chemical equilibrium can only be established in

    • Aan open beaker
    • Ba closed system
    • Cthe presence of a catalyst only
    • Dsolid reactions only

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12. Question 12· Chemical equilibrium· JAMB

    At dynamic equilibrium,

    • Aall reaction has stopped
    • Bthe forward and backward reactions occur at equal rates
    • Conly the forward reaction occurs
    • Donly products remain

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13. Question 13· Chemical equilibrium· JAMB

    For 2SO₂ + O₂ ⇌ 2SO₃ (ΔH negative), the yield of SO₃ increases when

    • Apressure is raised and temperature lowered
    • Bpressure is lowered
    • Ctemperature is raised
    • DSO₃ is added

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14. Question 14· Chemical equilibrium· JAMB

    For CaCO₃(s) ⇌ CaO(s) + CO₂(g) in a closed vessel, continuously removing the carbon(IV) oxide will

    • Ashift the equilibrium to the left
    • Bshift the equilibrium to the right
    • Chave no effect
    • Dstop the decomposition

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15. Question 15· Chemical equilibrium· JAMB

    For N₂(g) + 3H₂(g) ⇌ 2NH₃(g), increasing the pressure shifts the equilibrium

    • Ato the right
    • Bto the left
    • Cin neither direction
    • Dto stop the reaction

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16. Question 16· Chemical equilibrium· JAMB

    For N₂O₄ ⇌ 2NO₂ (ΔH positive), raising the temperature

    • Astops the reaction
    • Bshifts it to the left
    • Chas no effect
    • Dshifts the equilibrium to the right

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17. Question 17· Chemical equilibrium· JAMB

    Le Chatelier's principle states that when a system at equilibrium is disturbed, the system

    • Aalways moves to the right
    • Bstops reacting
    • Cshifts so as to oppose the disturbance
    • Dalways moves to the left

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18. Question 18· Chemical equilibrium· JAMB

    The equilibrium constant for N₂O₄(g) ⇌ 2NO₂(g) is

    • AK = [NO₂]/[N₂O₄]
    • BK = [N₂O₄]/[NO₂]²
    • CK = 2[NO₂]/[N₂O₄]
    • DK = [NO₂]²/[N₂O₄]

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19. Question 19· Chemical equilibrium· JAMB

    For 2NO₂(g) ⇌ N₂O₄(g), increasing the pressure

    • Ashifts the equilibrium to the left
    • Bshifts the equilibrium to the right
    • Chas no effect
    • Ddecomposes N₂O₄

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20. Question 20· Chemical equilibrium· JAMB

    In the Haber process, ammonia is removed from the equilibrium mixture by

    • Aburning it
    • Bdissolving it in oil
    • Ccooling, so that it liquefies
    • Dpassing it over iron

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