1: Rate & Extent Of Chemical Change Flashcards
What is a catalyst?
Substances that increase a chemical reaction’s rate without reducing in quantity during the reaction.
What happens to the quantity of a catalyst during a reaction?
Stays the same
How do catalysts increase the R.O.R?
Lower the activation energy, by changing the reaction pathway.
Can catalysts be reused?
Yes, indefinitely.
What treatment do catalysts often need?
Cleaning or regenerating. This has knock-on effects for energy expenditure and an environmental impact.
List the advantages of catalysts.
-Cost effective (a small amount can speed up a reaction by a lot, paying for a catalyst can be cheaper than paying for energy)
-Reduced burning of fossil fuels (because they don’t need to increase temperature)
State the disadvantage of a catalyst.
Many catalysts are toxic, and can escape into the environment and damage ecosystems.
What 5 things affect the rate of reaction?
-Temperature
-Concentration
-Surface Area : Volume Ratio
-Pressure
-Use of Catalyst
How does temperature affect the rate of reaction?
Increasing temperature gives particles more kinetic energy
This means the particles collide more often and with more energy
So more successful collisions
So increases the RoR
What happens to the RoR when surface area increases?
Rate of Reaction increases.
Explain how large surface area affects the RoR.
-Small pieces of reactant have a greater surface area : volume ratio.
-So there is more surface area for other reactant particles to collide with.
-So there are more frequent and successful collisions, which make the reaction happen faster.
-So increases the RoR
How does concentration affect the RoR?
When the concentration of a solution increases, the RoR increases.
Explain how concentration affects the Rate of Reaction.
-When concentration increases, there are more particles in the same amount of space
-So particles are closer together.
-This causes more frequent successful collisions.
-So the RoR increases.
How does pressure affect the rate of a reaction?
When pressure increases, the rate of reaction increases.
Explain how pressure affects the RoR.
-When the pressure increases, there are more reactant particles in a given volume.
-The higher the pressure, the closer the particles are to eachother.
-This causes more frequent successful collisions.
-So the RoR increases.
