JAMB Chemistry questions: Energy changes

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

1. Question 1· Energy changes· JAMB

   Forming new chemical bonds

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

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2. Question 2· 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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3. Question 3· 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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4. Question 4· 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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5. Question 5· 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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6. Question 6· 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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7. Question 7· 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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8. Question 8· 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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9. Question 9· Energy changes· JAMB

   On an energy profile diagram, adding a catalyst

   • Alowers the energy peak (activation energy)
   • Braises the energy of the products
   • Cchanges ΔH
   • Draises the energy peak

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10. Question 10· Energy changes· JAMB

    Breaking chemical bonds is

    • Aan endothermic process
    • Ban exothermic process
    • Cneither endothermic nor exothermic
    • Da nuclear process

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11. Question 11· Energy changes· JAMB

    Which of the following is an endothermic process?

    • Acombustion of petrol
    • Bphotosynthesis
    • Crespiration
    • Dneutralisation

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12. Question 12· Energy changes· JAMB

    The heat of combustion of a substance is the heat released when

    • Aone mole of it burns completely in oxygen
    • Bone gram of it melts
    • Cit dissolves in water
    • Dit is neutralised

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13. Question 13· Energy changes· JAMB

    Entropy is a measure of

    • Aits heat content
    • Bthe disorder of a system
    • Cits temperature
    • Dits pressure

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14. Question 14· Energy changes· JAMB

    A reaction with a negative ΔH is

    • Aexothermic
    • Bendothermic
    • Creversible
    • Dslow

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15. Question 15· Energy changes· JAMB

    In an exothermic reaction, the products have

    • Amore energy than the reactants
    • Bless energy than the reactants
    • Cthe same energy as the reactants
    • Dno energy

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16. Question 16· Energy changes· JAMB

    In a reaction, 1000 kJ is absorbed in breaking bonds and 1200 kJ is released in forming bonds. Find ΔH.

    • A−2200 kJ
    • B+200 kJ
    • C−200 kJ
    • D+2200 kJ

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17. Question 17· Energy changes· JAMB

    The standard enthalpy of formation of an element in its standard state is

    • Aalways negative
    • B100 kJ/mol
    • Czero
    • Dalways positive

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18. Question 18· Energy changes· JAMB

    For 2H₂(g) + O₂(g) → 2H₂O(l), ΔH = −572 kJ. How much heat is released when 1 g of hydrogen burns? (H = 1)

    • A143 kJ
    • B286 kJ
    • C572 kJ
    • D71.5 kJ

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19. Question 19· Energy changes· JAMB

    The minimum energy that colliding particles must have before they react is the

    • Aenthalpy of reaction
    • Bactivation energy
    • Clattice energy
    • Dionisation energy

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20. Question 20· Energy changes· JAMB

    

    The energy profile shown represents a reaction that is

    • Aat equilibrium
    • Bendothermic
    • Cexothermic
    • Dnot a chemical change

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