C8.5 The effect of catalysts Flashcards
What are catalysts?
A substance that changes the rate of reaction
How do catalysts increase the rates of reaction?
By providing an alternative reaction pathway to the products with a lower activation energy
What happens when a catalyst is present?
The particles require less energy to cross the activation energy barrier
Explain how catalysts work?
The provide an alternative pathway to the products with lower activation energy
Higher proportion of particles of the reactant particles have sufficient energy to react
Frequency of successful collisions increase
What type of metals are used in catalytic convertors?
Platinum and Palladium
Why do catalysts help the environment?
Operating at low temperatures and pressure conserves these non- renewable resources
Why do catalysts sometimes stop working?
They eventually become poisoned - this happens because impurities in the reaction mixture combine with the catalyst and stop it from working properly
How can you investigate catalysts?
You can use hydrogen peroxide solution decomposing with several catalysts
Measure the time taken to get a fixed amount of oxygen
Plot a graph to see which catalyst makes the reaction go faster
Why do catalysts do not appear in the balance equation for a reaction?
Because they only change the rate of reactions. The products do not change
Why are catalysts used in the industry?
To reduce energy costs
Increase rates of reactions
