JAMB and WAEC Chemistry questions

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

1. Question 221· Chemical equilibrium· WAEC

   In the Contact process, the catalyst used is

   • Airon
   • Bvanadium(V) oxide
   • Cplatinum only
   • Dnickel

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   Explanation and discussion

2. Question 222· Chemical equilibrium· WAEC

   Raising the temperature of an exothermic reaction at equilibrium shifts the equilibrium

   • Anowhere
   • Bto the right
   • Cto the left
   • Duntil the reaction stops

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   Explanation and discussion

3. Question 223· 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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4. Question 224· 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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   Explanation and discussion

5. Question 225· 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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6. Question 226· 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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7. Question 227· 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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8. Question 228· Chemical equilibrium· WAEC

   For the reaction N₂ + 3H₂ ⇌ 2NH₃, increasing the pressure

   • Ashifts the equilibrium to the right
   • Bshifts the equilibrium to the left
   • Chas no effect
   • Dstops the reaction

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9. Question 229· Chemical equilibrium· WAEC

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

   • Adoes not alter the position of equilibrium
   • Bshifts it to the right
   • Cshifts it to the left
   • Ddoubles the amount of HI

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10. Question 230· 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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11. Question 231· Chemical equilibrium· WAEC

    For the exothermic reaction N₂(g) + 3H₂(g) ⇌ 2NH₃(g), raising the temperature

    • Ashifts the equilibrium to the left and lowers the yield of ammonia
    • Bshifts the equilibrium to the right
    • Chas no effect on the yield
    • Dincreases the yield of ammonia

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12. Question 232· 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 233· 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 234· Chemical equilibrium· WAEC

    Heating blue hydrated copper(II) tetraoxosulphate(VI) turns it white; adding water turns it blue again. This shows that the change is

    • Aa combustion
    • Birreversible
    • Ca physical change only
    • Dreversible

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15. Question 235· 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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16. Question 236· Chemical equilibrium· WAEC

    Dynamic equilibrium means

    • Aonly reactants remain
    • Bthe reaction has stopped
    • Conly products remain
    • Dforward and backward reactions continue at equal rates

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17. Question 237· Chemical equilibrium· WAEC

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

    • Agoes to completion
    • Bstops reacting
    • Cshifts so as to oppose the change
    • Dreleases all its energy

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18. Question 238· 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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19. Question 239· Chemical equilibrium· WAEC

    A reaction that can proceed in both the forward and backward directions is

    • Areversible
    • Birreversible
    • Cexothermic only
    • Da combustion

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20. Question 240· Chemical equilibrium· WAEC

    A catalyst added to a system at equilibrium

    • Ashifts the equilibrium to the right
    • Bspeeds up both forward and backward reactions equally
    • Cincreases yield
    • Dstops the reaction

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    Explanation and discussion