Rates Of Reaction Flashcards
How is rate calculated
Rate = 1/time
Name 3 practical measures to measure the rate of reaction
- Measuring the volume of gas produced over a certain time using a gas syringe.
- Measuring the change in mass over a period of time due to loss of gas. Ensure cotton wool plug is used to prevent spitting of liquid
- Measuring amount of time taken for precipitate to form.
Define activation energy
It is the minimum energy required for a reaction to occur.
How does concentration effect reaction rates
If the concentration is increased there will be more particles in the same volume so there are more collisions. Therefore in a certain period of time there are more collisions with the activation energy therefore rate of reaction increases
How does surface area increase rate of reaction?
In a reaction with a solid only the particles on the surface can react through collision. Therefore if a large object is broken up into smaller pieces the surface area can increase. This allows more particles to be exposed to the other reactant, this allows for a faster rate of reaction.
How does temperature effect rate of reaction
At low temperatures the particles collide will less than the activation energy so many collisions are unsuccessful. As temperature increases the particles have more kinetic energy this means the particles are likely to have equal to or greater than the activation energy. This therefore results in more successful collisions so rate of reaction increases.
Define catalyst
A substance that increases the rate of reaction without being used up.
How do catalysts increase the rate of reaction?
Catalysts lower the activation energy of a reaction. This means more reactions will have sufficient activation energy to overcome the energy barrier to form products.
What are catalysts usually made from
Transition metals
