JAMB Chemistry questions

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

1. Question 181· 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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2. Question 182· 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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3. Question 183· 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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4. Question 184· 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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5. Question 185· 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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6. Question 186· 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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7. Question 187· 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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8. Question 188· Energy changes· JAMB

   Breaking chemical bonds is

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

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9. Question 189· Energy changes· JAMB

   Which of the following is an endothermic process?

   • Acombustion of petrol
   • Bphotosynthesis
   • Crespiration
   • Dneutralisation

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10. Question 190· 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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11. Question 191· Energy changes· JAMB

    Entropy is a measure of

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

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12. Question 192· Energy changes· JAMB

    A reaction with a negative ΔH is

    • Aexothermic
    • Bendothermic
    • Creversible
    • Dslow

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13. Question 193· 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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14. Question 194· 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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15. Question 195· 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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16. Question 196· 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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17. Question 197· 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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18. Question 198· Energy changes· JAMB

    

    The energy profile shown represents a reaction that is

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

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19. Question 199· Energy changes· JAMB

    The combustion of 1 mol of methane releases 890 kJ. How much heat is released when 4 g of methane burns? (C = 12, H = 1)

    • A445 kJ
    • B890 kJ
    • C3560 kJ
    • D222.5 kJ

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20. Question 200· Energy changes· JAMB

    An exothermic reaction is one in which:

    • Aheat is absorbed
    • Bheat is released
    • Cno heat change occurs
    • Dthe temperature falls

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