What is activation energy?
The minimum energy needed for a reaction to occur.
AQA GCSE Combined Science: Trilogy (8464) — Chemistry — Higher · 5.6.1.3
Revise AQA GCSE Combined Science: Trilogy (8464) — Chemistry — Higher specification point 5.6.1.3, Collision theory and activation energy, with free active-recall flashcards. Flip through the set or review every question and answer below.
1 / 16
What is activation energy?
The minimum energy needed for a reaction to occur.
What energy condition must a particle collision satisfy to be successful?
The particles must collide with enough energy to overcome the activation energy.
Which two collision-related factors determine reaction rate?
How often particles collide and how many collisions have sufficient energy.
What does a faster reaction mean in terms of successful collisions?
There are more successful collisions each second.
In a simple collision model, how does a change in collision opportunities per second relate to the change in reaction rate?
The reaction rate changes by approximately the same factor.
In a simple collision model, why does having more particles in the same volume increase the reaction rate?
Collisions happen more often, so the rate increases.
What happens to the number of reactant particles in a fixed volume when solution concentration increases?
There are more reactant particles in the same volume.
What happens to the spacing of reacting gas particles when pressure increases?
The particles are packed more closely together.
How do increased concentration or gas pressure make a reaction faster?
More particles per unit volume cause more frequent collisions, increasing the number of successful collisions per second.
How does raising the temperature affect the kinetic energy of reacting particles?
It increases their kinetic energy.
Why does raising the temperature increase the frequency of collisions between reacting particles?
The particles move faster, so they collide more often.
Why does raising the temperature increase the proportion of successful collisions?
Collisions become more energetic, so a greater proportion have enough energy to overcome the activation energy.
What effect does raising the temperature have on reaction rate?
It increases the reaction rate.
Where can other reacting particles collide with a solid reactant?
At its exposed surface.
How does breaking the same amount of solid into smaller pieces affect its exposed surface area and surface area to volume ratio?
It increases both the total exposed surface area and the surface area to volume ratio.
Why do smaller pieces of a solid react faster than larger pieces under otherwise unchanged conditions?
Their greater exposed surface allows more particle collisions per second, causing more successful collisions per second.