JAMB and WAEC Chemistry questions

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

1. Question 321· Electrolysis· JAMB

   During electrolysis, positive ions (cations) move towards the

   • Aelectrolyte surface
   • Banode
   • Ccathode
   • Dsalt bridge

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2. Question 322· Electrolysis· JAMB

   In the purification of copper by electrolysis, the impure copper is made the

   • Aanode
   • Bcathode
   • Celectrolyte
   • Dsalt bridge

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3. Question 323· Electrolysis· JAMB

   Sodium is obtained industrially by electrolysing

   • Asodium trioxocarbonate(IV) solution
   • Bbrine
   • Csea water
   • Dmolten sodium chloride

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4. Question 324· Electrolysis· JAMB

   The same charge passes through solutions of AgNO₃ and CuSO₄ in series. If 0.2 mol of silver is deposited, how many moles of copper are deposited?

   • A0.4
   • B0.2
   • C0.1
   • D0.05

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5. Question 325· Electrolysis· WAEC

   Very dilute sodium chloride solution is electrolysed with inert electrodes. The main gas at the anode is

   • Ahydrogen
   • Bchlorine
   • Csodium
   • Doxygen

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6. Question 326· Energy changes· WAEC

   Which combination makes a reaction spontaneous (ΔG negative) at every temperature?

   • Apositive ΔH and negative ΔS
   • Bnegative ΔH and positive ΔS
   • Cpositive ΔH and positive ΔS
   • Dnegative ΔH and negative ΔS

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7. Question 327· Energy changes· JAMB

   Forming new chemical bonds

   • Ahas no energy change
   • Babsorbs energy
   • Cneeds a catalyst
   • Dreleases energy

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8. Question 328· Energy changes· JAMB

   The heat of neutralisation of a strong acid by a strong base is about

   • A−57 kJ per mole of water formed
   • B+57 kJ per mole
   • C−890 kJ per mole
   • D0 kJ per mole

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9. Question 329· Energy changes· JAMB

   When ammonium chloride dissolves in water, the temperature of the water

   • Arises and then falls
   • Brises
   • Cstays the same
   • Dfalls

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10. Question 330· Energy changes· JAMB

    Bond energy is the energy

    • Aof one electron
    • Breleased when a solid melts
    • Cneeded to break one mole of a particular bond
    • Dneeded to boil one mole of a liquid

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11. Question 331· Energy changes· WAEC

    Dissolving ammonium chloride in water makes the beaker feel cold. The process is

    • Aa neutralisation
    • Bexothermic
    • Ca redox reaction
    • Dendothermic

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12. Question 332· Energy changes· JAMB

    In which of the following changes does entropy increase?

    • Aa gas being compressed
    • Bsteam condensing
    • Cice melting
    • Dwater freezing

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13. Question 333· Energy changes· JAMB

    The enthalpy of combustion of methane is −890 kJ/mol. How much heat is released when 8 g of methane burns? [C = 12, H = 1]

    • A445 kJ
    • B890 kJ
    • C1,780 kJ
    • D111 kJ

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14. Question 334· Energy changes· JAMB

    Enthalpy changes that cannot be measured directly can be calculated using

    • ABoyle's law
    • BHess's law
    • CGraham's law
    • DFaraday's law

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15. Question 335· Energy changes· JAMB

    Hess's law states that the enthalpy change of a reaction

    • Adepends on the catalyst
    • Bis the same whatever route is taken
    • Cis always negative
    • Ddepends on the rate of reaction

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16. Question 336· Energy changes· WAEC

    The heat of combustion of a substance is the heat

    • Aevolved when one mole burns completely in oxygen
    • Babsorbed when one mole melts
    • Cevolved on dissolving
    • Dneeded to boil one mole

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17. Question 337· Energy changes· WAEC

    Dissolving ammonium nitrate in water makes the solution cold because the process is

    • Aa combustion
    • Bexothermic
    • Cendothermic
    • Dneutralisation

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18. Question 338· Energy changes· WAEC

    A reaction in which heat is absorbed from the surroundings is

    • Areversible
    • Bexothermic
    • Ccatalytic
    • Dendothermic

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19. Question 339· Energy changes· WAEC

    50 cm³ of 1.0 mol/dm³ HCl is mixed with 50 cm³ of 1.0 mol/dm³ NaOH and 2.85 kJ of heat is released. Find the heat of neutralisation.

    • A−114 kJ/mol
    • B−2.85 kJ/mol
    • C−28.5 kJ/mol
    • D−57 kJ/mol

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20. Question 340· Energy changes· WAEC

    When ammonium chloride dissolves in water, the solution becomes cold. The process is

    • Aexothermic
    • Bneutralisation
    • Cendothermic
    • Dcombustion

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    Explanation and discussion