Rates of Reaction Flashcards
How can the rate of reaction be calculated?
1/t
Units for rate - 1/s
What can you use on a graph to tell you how fast the reaction is?
Gradient
What reactions can be used to test rate of reaction?
Metals with dilute acid
Calcium carbonate with dilute acid
Catalytic decomposition of hydrogen peroxide to produce oxygen
Sodium thiosulfate with acid
What is collision Theory?
For a reaction to happen particles must collide together with enough energy to react.
Successful collisions are ones that result in a reaction and they take place when reactant particles collide with the activation energy.
Unsuccessful collisions are ones that do not result in a reaction as the particles collide with less than the activation energy
What is activation energy?
The minimum energy required for a reaction to occur
What can affect the rate of reaction?
Concentration
Surface Area
Temperature
Catalysts
How does concentration affect rate of reaction?
Low concentration there are few particles in a given space so there are few successful collisions.
When concentration is increased there are more particles in the same volume so there will be more collisions. Per unit time there are more collisions with activation energy there rate increases
How does surface area affect rate of reaction?
Only particles on a solid on the surface are available to react through collision.
A large piece of solid has a low surface area as only few particles can react.
If the solid is broken into smaller pieces the surface area is increased and more particles are exposed to the other reactant. Therefore more frequent successful collisions per unit of time.
How does temperature affect rate of reaction?
Low temp the particles collide with less than the activation energy so many collisions are unsuccessful.
As the temp of the reaction is increased there particles have more energy and therefore are likely to have energy to equal or greater than activation energy.
How do catalysts affect the rate of reaction?
Catalysts increase the rate by lowering the activation energy of a reaction.
This means that in a catalytic reaction when particles collide more of them have sufficient energy to overcome the energy barrier to form products and the reaction is faster
What can the catalysts Fe, Pt, Ag and alloy of Rh be used for?
Fe - haber process to produce ammonia
Pt - cracking of hydrocarbons
Ag - production of ethanol from ethene
Rh - catalytic converters in cars
What are catalysts used for?
Important in increasing the rate of reaction used in industrial processes to reduce costs and help the environment. They are often transition metals
