rates of reaction Flashcards
(12 cards)
Particle collision theory
For a chemical reaction to occur, particles must collide with sufficient energy to overcome the energy barrier.
How does increasing temperature affect reaction rates?
More frequent successful collisions occur as more particles have enough kinetic energy to overcome the activation energy.
How does increasing concentration affect reaction rates?
More reactant particles per volume lead to more frequent collisions.
How does increasing surface area affect reaction rates?
More opportunities for collisions to occur result in more frequent successful collisions.
What does a catalyst do?
Increases the rate of reaction but is not chemically changed or used up during the reaction.
How does adding a catalyst affect a reaction?
A catalysed reaction requires less energy to occur, leading to more frequent successful collisions.
How does a catalyst work?
By providing an alternative pathway with lower activation energy.
What is the activation energy?
The minimum amount of energy needed for the particles to react.
What is a surface area practical experiment?
Using marble chips in hydrochloric acid to measure gas production by changing the size of marble chips, e.g., using powder.
What is the concentration practical?
Marble chips and hydrochloric acid are used to observe how much gas is produced with changes in the concentration of acid.
What is the temperature practical?
Sodium thiosulfate solution and hydrochloric acid are used to measure how long it takes for the cross to disappear in different temperature water baths.
What is the catalyst practical?
Solids are added to hydrogen peroxide solution to calculate the amount of solid left at the end of the reaction. The best solid causes bubbles and isn’t used up.
