Lesson 3.1.5a

3.1.5a Kinetics Quiz: AQA Chemistry, Unit 1

20 questions

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Lesson 3.1.5a, Kinetics: 20 multiple choice questions for the AQA Chemistry (7405), Unit 1: Physical chemistry, written with Revision Ninja.

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The 20 questions

  1. What does the study of kinetics allow chemists to determine?

    • The equilibrium position of a reaction only, once the reaction has reached balance
    • The enthalpy change of a reaction, measured at constant pressure in a calorimeter
    • How a change in conditions affects the speed of a chemical reaction
    • The number of protons in an atom, found from the mass spectrum of the element
  2. Alongside reaction conditions, which factor is significant in how fast a reaction proceeds?

    • The reactivity of the chemicals involved
    • The mass of the laboratory building
    • The number of spectator ions only
    • The colour of the reaction vessel
  3. What is the rate of a reaction?

    • The change in amount of a reactant or product per unit time
    • The temperature at which a reaction ends, measured when the mixture stops changing
    • The number of steps in a reaction mechanism, counted from reactants to products
    • The total mass of reactants at the start of the reaction, measured before mixing
  4. Which condition can be changed to speed up a reaction?

    • Atomic number of the reactants
    • Mass of the chemist
    • Colour of the reaction vessel
    • Temperature
  5. Which change reduces the rate of a reaction?

    • Increasing the concentration
    • Increasing the pressure of a gas
    • Lowering the temperature
    • Adding a catalyst
  6. Which unit is commonly used for the rate of a reaction measured by concentration?

    • dm3 K-1
    • g mol-1
    • mol dm-3 K
    • mol dm-3 s-1
  7. What does a faster reaction mean?

    • The rate is greater, so the product forms in less time
    • The rate is lower, so the product forms more slowly
    • No change in product forms
    • Equilibrium is reached
  8. The concentration of a reactant falls from 0.80 mol dm-3 to 0.40 mol dm-3 in 40 s. What is the average rate?

    • 0.0200 mol dm-3 s-1
    • 0.400 mol dm-3 s-1
    • 0.0100 mol dm-3 s-1
    • 0.00500 mol dm-3 s-1
  9. A gas is produced with a mass of 0.24 g in 60 s. What is the average rate of production?

    • 0.24 g s-1
    • 0.0040 mol s-1
    • 60 g s-1
    • 0.004 g s-1
  10. A reaction collects 36 cm3 of gas in 30 s. What is the average rate?

    • 36 cm3 s-1
    • 1080 cm3 s-1
    • 1.2 cm3 s-1
    • 0.83 cm3 s-1
  11. On a graph of mass against time for a reaction producing gas, what does a steeper gradient indicate?

    • A reaction that has stopped
    • A reaction with a negative rate
    • A faster reaction
    • A slower reaction
  12. How is the initial rate of a reaction found from a concentration-time graph?

    • By averaging the whole curve, which gives the rate across the complete reaction time
    • By finding the time to reach the end point, then dividing the total change by it
    • By measuring the gradient of the tangent at time zero
    • By reading the final value only, which shows how much product formed in total
  13. A reaction takes 50 s. If the rate doubles, roughly how long does the reaction take?

    • 25 s
    • 12.5 s
    • 100 s
    • 50 s
  14. A reaction gives 0.50 mol of product in 25 s. What is the average rate?

    • 0.5 mol s-1
    • 0.02 mol s-1
    • 0.0500 mol s-1
    • 12.5 mol s-1
  15. How is the rate of reaction found in an experiment?

    • By measuring the mass of the flask only, once at the start and once at the end
    • By calculating the equilibrium constant from the concentrations at the end of the reaction
    • By measuring how quickly a reactant is used up or a product forms over time
    • The rate is the same as the percentage yield, calculated from the final product mass
  16. Why does the rate of a typical reaction decrease as the reaction proceeds?

    • Products increase the activation energy of the reaction as they build up in the mixture
    • The temperature rises during the reaction, which slows the particles down over time
    • The catalyst is used up during the reaction, so no further acceleration of the rate occurs
    • Reactant concentration falls, so collisions become less frequent
  17. The concentration of a reactant falls from 0.50 to 0.20 mol dm-3 in 100 s. What is the average rate?

    • 0.0015 mol dm-3 s-1
    • 0.300 mol dm-3 s-1
    • 0.0030 mol dm-3 s-1
    • 0.0070 mol dm-3 s-1
  18. Why is the initial rate often measured instead of an average rate over the whole reaction?

    • The initial rate avoids the need for a graph, because it is found from a single reading of mass
    • The rate changes as reactants are used up, so the initial gradient gives the rate at known starting concentrations
    • Average rates are always inaccurate, because they are calculated from the whole reaction curve
    • Products have no effect on the rate, so the start of the reaction is the only useful reading
  19. The mass of a flask falls from 2.00 g to 1.20 g in 40 s as gas escapes. What is the average rate?

    • 0.0200 g s-1
    • 0.800 g s-1
    • 0.0800 g s-1
    • 0.0120 g s-1
  20. The rate at condition A is 0.40 mol dm-3 s-1 and the rate at condition B is 0.10 mol dm-3 s-1. How many times faster is A than B?

    • Two times faster
    • Four times faster
    • Ten times faster
    • The same speed

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