Rate of Reaction

HKDSE Tip

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  Collision theory:

  Higher reactant concentration increases particle numbers and effective collision frequency.
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  Temperature:

  Higher temperature increases average kinetic energy so more collisions exceed $E_a$.
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  Rate constant (k):

  The value of $k$ is constant at a constant temperature, but it changes if temperature changes. A higher temperature increases $k$, which speeds up the reaction rate.
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  Catalyst:

  A catalyst lowers activation energy and speeds up the reaction without shifting equilibrium.
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  Observation:

  This acid–carbonate reaction releases CO₂; effervescence rate illustrates how concentration and temperature affect reaction rate.