Chemical reactions can occur only when reactingparticlescollide with each other with sufficientenergy
Activation energy
The minimum amount of energy that particles must have to have successfulcollisions and react
C: Increasing surface area
Means moresites for reaction to occur leading to more frequentcollisions
C: Increasing temperature
Causes particles to gain kinetic energy/move faster, so particles collide more frequently and with more energy, meaning a higherproportion will have activation energy
C: Increasing concentration
Moreparticles in the samevolume: therefore morefrequentcollisions
C: Increasing pressure
Squashing gas particles more closelytogether-moreparticles of gas in a given space
C: Adding a catalyst
Provides the reaction an alternatepathway, so a greaterproportion of particles can now collide successfully, they aren’t used up in reactions
RQ: Investigating the effect of concentration on rate of reaction
This experiment is carried out by measuring the rate of reaction using one of the methods of measuring RR and repeating for differentconcentrations of a reactant to see the effect
Equilibrium
In a closed system, an equilibrium is reached where the rateofreaction is the same in bothdirections, so the overallamounts of the reactants and productsdon’tchange.
Le Chatelier’s principle
If the dynamic equilibrium is disturbed by changing the conditions, the position of the equilibrium shifts to counteract the change to re-establish an equilibrium
E: Temperature increased
Equilibrium shifts to favour the endothermic reaction
E: Temperature decrease
Shift to favour exothermic reaction
E: Pressure increase
Shift towards side with smallernumber of gasmolecules
E: Pressure decrease
Shift towards side with largernumber of gasmolecules
E: Pressure if the number of gas molecules is the same
Noeffect
E: Concentration decrease
Shifts to the left to make morereactants react until equilibrium is reached again
E: Concentration increase
Shift towards right to form moreproducts until equilibrium is reached