JAMB and WAEC Chemistry questions: Rates of chemical reaction

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

1. Question 1· Rates of chemical reaction· JAMB

   Sunlight speeds up the reaction between hydrogen and chlorine because it

   • Asupplies energy to break Cl–Cl bonds
   • Bcools the mixture
   • Cis a reactant
   • Dremoves the product

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2. Question 2· Rates of chemical reaction· JAMB

   Which of the following reactions is greatly speeded up by light?

   • Azinc and dilute acid
   • Bhydrogen and chlorine forming hydrogen chloride
   • Cneutralisation of an acid by an alkali
   • Ddecomposition of limestone

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3. Question 3· Rates of chemical reaction· JAMB

   The rate of a reaction is greatest at the start and falls with time because

   • Amore products slow the reaction
   • Bthe catalyst is used up
   • Cthe temperature always falls
   • Dthe concentration of the reactants decreases

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4. Question 4· Rates of chemical reaction· JAMB

   

   In the energy profile shown, the energy labelled X is the

   • Aactivation energy
   • Benthalpy change of the reaction
   • Cenergy of the products
   • Dbond energy of the products

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5. Question 5· Rates of chemical reaction· JAMB

   Photographic film works because silver halides

   • Abecome magnetic
   • Bmelt in light
   • Cdissolve in light
   • Ddecompose when exposed to light

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6. Question 6· Rates of chemical reaction· JAMB

   Increasing the concentration of an acid increases its rate of reaction with marble because

   • Athe marble becomes larger
   • Bthe activation energy rises
   • Cthe reacting particles collide more often
   • Dthe temperature falls

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7. Question 7· Rates of chemical reaction· JAMB

   Enzymes are

   • Ametals
   • Binorganic acids
   • Csimple sugars
   • Dbiological catalysts

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8. Question 8· Rates of chemical reaction· JAMB

   A suitable unit for the rate of reaction measured as change in concentration with time is

   • Amol dm⁻³ s⁻¹
   • Bmol dm⁻³
   • Cs⁻¹ only
   • DkJ mol⁻¹

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9. Question 9· Rates of chemical reaction· JAMB

   A substance that slows down a chemical reaction is called

   • Aa catalyst
   • Ban inhibitor
   • Ca reactant
   • Dan enzyme only

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10. Question 10· Rates of chemical reaction· WAEC

    Which of the following increases the rate of reaction between marble and dilute hydrochloric acid?

    • AUsing larger marble chips
    • BDiluting the acid
    • CCooling the acid
    • DUsing powdered marble

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11. Question 11· Rates of chemical reaction· WAEC

    Hydrogen peroxide decomposes faster when manganese(IV) oxide is added. The manganese(IV) oxide

    • Ais used up in the reaction
    • Bis a catalyst and is unchanged at the end
    • Cis a reactant
    • Dslows the reaction down

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12. Question 12· Rates of chemical reaction· WAEC

    Powdered marble reacts faster with dilute acid than marble chips of the same mass because the powder

    • Ais a different compound
    • Bhas a greater mass
    • Chas a larger surface area
    • Dis more concentrated

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13. Question 13· Rates of chemical reaction· JAMB

    A negative catalyst (inhibitor)

    • Achanges ΔH
    • Bspeeds up a reaction
    • Cslows down a reaction
    • Dstarts a reaction

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14. Question 14· Rates of chemical reaction· WAEC

    The rate of a reaction can be followed by measuring

    • Athe size of the beaker
    • Bthe colour of the flask
    • Cthe volume of gas given off over time
    • Dthe room temperature

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15. Question 15· Rates of chemical reaction· WAEC

    For many reactions, a 10 °C rise in temperature roughly

    • Adoubles the rate
    • Bhalves the rate
    • Cleaves the rate unchanged
    • Dincreases the rate tenfold

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16. Question 16· Rates of chemical reaction· JAMB

    Increasing the concentration of reactants increases the rate because

    • Athe catalyst is used up
    • Bactivation energy falls
    • CΔH changes
    • Dcollisions become more frequent

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17. Question 17· Rates of chemical reaction· WAEC

    A catalyst speeds up a reaction by

    • Araising the temperature
    • Bproviding a pathway with lower activation energy
    • Cmaking ΔH larger
    • Dshifting the equilibrium to the right

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18. Question 18· Rates of chemical reaction· JAMB

    The rate of the reaction between magnesium and dilute hydrochloric acid can be followed by collecting the hydrogen in a

    • Apipette
    • Bburette
    • Cgas syringe
    • Dcrucible

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19. Question 19· Rates of chemical reaction· JAMB

    According to the collision theory, a reaction takes place when particles collide

    • Aonly when heated
    • Bat any speed
    • Conly in the solid state
    • Dwith enough energy and in the right orientation

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20. Question 20· Rates of chemical reaction· JAMB

    The rate of a reaction that gives off a gas can be followed by measuring the

    • Acolour of the container
    • Bvolume of gas produced per unit time
    • Cmass of the burner
    • Dsize of the beaker

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    Explanation and discussion