Rates of energy Flashcards
How do you measure the rate of a reaction
Amount of reactant used OR amount of product formed / time
What is the collision theory
States that reactions can only happen if particles collide with enough energy to form new products
What is the activation energy
The minimum energy needed to collide the particles into new substances
What factors will increase the energy of the particles and thus the chance of collisions. The rate of reaction is increased by this.
Temperature, concentration, pressure, surface area, catalyst
How does temperature increase the rate of reaction
Increases the speed of the particles and increases the energy they hit with, which increases the frequency of collisions and speeds the rate of reaction up
How does surface area increase the rate of reaction
More area for the particles to hit each other, more collisions at the same time and this speeds up the rate of reaction
How does pressure and concentration effect rate of reaction
A higher concentration means there are more particles in the same volume which increases the chance of the particles colliding as they are closer together. This increases the rate of reaction. As with pressure, more particles are added.
How do catalysts effect the rate of reaction
Lower the activation energy so less energy is needed to change into substances. More of the collisions result in a reaction. Catalysts can be reused.
Give 2 advantages and 1 disadvantage of using catalysts
D: Expensive
A: Only economical if reused (so in industry) and this can reduce costs and resources and energy needed to react.
Also reduces pollution because less energy is needed from fossil fuels
Difference between an endothermic and an exothermic reaction
Endo: Take energy in from the surroundings
Exo: Release energy into the surroundings
If a reaction is reversible can it be exothermic both ways?
NO!
Must be opposite the opposing way
Give an advantage and disadvantage of using reheatable hand warmers
A: Can be reused many times as it’s an exothermic reaction
D: Needs to be reheated every time
Give a real life example of an endothermic reaction
Cold ice pack
