Topic 4- Rates of Reaction Flashcards
The decomposition of hydrogen peroxide is catalysed by adding a small amount of manganese oxide. How will the graph of the reaction of the catalyst look like?
The graph will be a straight line/ horizontal because a catalyst doesn’t get used up.
In terms of the behaviour of particles, the effect of changing temperature and the effect of changing the concentration of a solution.
the temperature will give the particles more energy. They will also move faster and have more frequent and more energetic collisions.
How do you find the rate of reaction using a gradient?
Change in Y/ Change in X
Why are catalysts important?
+Reactions are quicker +They happen at lower temperatures +So it is cheaper to make a product
What is an endothermic reaction?
A reaction that takes in energy from the surroundings.
Shown by a fall in temperature of the surroundings.
What is an exothermic reaction?
A reaction which give out energy to surroundings.
Shown by a rise in temperature of the surroundings.
Why does increasing pressure of a gas increase the rate of reaction?
The higher the pressure the faster the reaction.
Particles are closer together in a decreased volume
So there there would be more frequent collisions.
What does a catalyst do to the activation energy?
The catalyst lowers the activation energy. + this means many more collisions are likely to be successful.
What is an anomalous result?
+Does not fit on best line of fit +Higher or lower than expected
What is a catalyst?
+A substance that speeds up chemical reactions without getting used up in the process or being chemically changed.
What is the rate of reaction?
How fast a reaction takes place.
How do you find the rate of a chemical reaction?
The amount of product made or the amount of reactant used up
What is activation energy
The minimum amount of energy required to start a reaction
What are the five factors affecting a reaction
- Concentration
- Temperature
- Catalyst
- Surface area
- Pressure (gases)
What does a higher concentration do to a reaction?
- More collisions
- More successful collisions
- More frequent collisions
- Faster rate of reaction
Why don’t all collisions between particles result in a chemical reaction?
Because sometimes they don’t have enough energy e.g heat
What effect does surface area have on the rate of reaction
- The particles are more exposed to the solution
- More area to react on
Therefore the frequency of collision increases resulting in increase of successful collisions
What is a catalyst and what effect does it have on the rate of a reaction
A catalyst will speed up the rate of a reaction by lowering the activation energy, it gives an alternative pathway for the particles to react on and it doesn’t get used up in a reaction
What increases the rate of reaction
Increasing the concentration of the reactant
What increases the rate of reaction of a solid
Increasing its surface area
What happens when the reactant has smaller particles
The rate of reaction increases
What happens when you increase the temperature
The rate of reaction increases
