Explaining what's happening
3 marks · EasyA student investigates how fast sodium reacts with water to produce hydrogen gas at room temperature.
State what must happen to sodium and water particles for this reaction to occur.
According to collision theory, what is a successful collision?
Explain why the reaction rate might change during the experiment.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) They must collide with each other.
(b) A collision with energy greater than or equal to the activation energy, resulting in a reaction.
(c) The reaction rate falls as sodium or water is used up, so the number of collisions per second decreases.
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States particles must collide for a reaction.
B2 (b) · 1 mark · Defines a successful collision as one with enough energy (activation energy) that leads to a reaction.
B3 (c) · 1 mark · Explains that as reactants are used the rate drops due to fewer collisions per second.
Worked solution
a) Sodium and water particles must collide for the reaction to occur.
b) A successful collision is one where the particles have enough energy, at least the activation energy, causing a reaction.
c) The reaction rate drops as sodium or water runs out, because fewer particles remain for collisions.