Rates of Reaction: Collision Theory and What Changes a Rate · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Crashes, dials and curve reading

Science · Matter & Materials · ages 15-16
Name ______________________   Date ____________

  1. Why does powdered marble react faster with acid than large chips?

    • Powder changes the acid concentration
    • Large chips absorb the catalyst
    • Powder exposes more surface for collisions

  2. What must happen for a reaction to occur?

    • Particles sit still in neat rows
    • Particles collide with enough energy and the right facing
    • The flask is shaken once at the start

  3. A catalyst is used up during the reaction it speeds.

    Circle one:   True   False

  4. 60 cm3 of gas forms in the first 30 s. What is the mean rate in cm3/s?

    Answer: ______________

  5. Why does warming speed most reactions?

    • It removes the activation energy entirely
    • It gives more collisions enough energy and raises meeting rates
    • It freezes particles into the right facing

  6. Two curves on the same axes level at the same total, but A starts steeper. What does this mean?

    • A made more gas overall
    • A used a different acid
    • A is the faster run with the same final amount

  7. How does a catalyst speed a reaction without being used up?

    • It lowers the activation energy so more collisions succeed
    • It raises the temperature of the mixture
    • It adds extra reactant particles

  8. A flask loses 4.8 g over 120 s. What is the mean rate of mass loss in g/s?

    Answer: ______________

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Answer key

For grown-ups. Fold this page away before handing over the rest.

Crashes, dials and curve reading W1-mt_Ma2bOotr9g-s1

  1. Powder exposes more surface for collisions · More exposed faces mean more places for acid particles to strike.
  2. Particles collide with enough energy and the right facing · Only a hard, well-aimed crash can rearrange bonds.
  3. False · It opens an easier path and emerges unchanged to repeat.
  4. 2 · 60 divided by 30 gives 2 cm3/s.
  5. It gives more collisions enough energy and raises meeting rates · Heat both energises collisions and makes them meet more often.
  6. A is the faster run with the same final amount · Steeper means faster, while the shared level means equal totals.
  7. It lowers the activation energy so more collisions succeed · A lower hump lets more of the same collisions over it.
  8. 0.04 · 4.8 divided by 120 gives 0.04 g/s.
Worksheet · LightMySky