[Music] hi and welcome back to three sighs lessons Cole you K by the end of this video you should be able to describe the effective change in the temperature on a reversible reaction at equilibrium and this is for higher-tier students only now I should point out that some students find this tricky you might need to watch this video a couple of times in the last video we looked at lush ateliers principle this states that if a systems at equilibrium and the changes made to the conditions then the system responds to counteract the change we looked at the effect of changing concentration on reversible reactions but in this video we're looking the effect of temperature take a look at this reaction which we saw in the previous video the reactant no.2 is forming the product n2o4 and this is a reversible reaction now a key point about this reaction is that the forward reactions exothermic what that means is that when the forward reaction takes place energy is released and the temperature of the system increases remember that in a reversible reaction if the reactions exothermic and one direction then it's endothermic in the opposite direction so in this case the reverse reaction must be endothermic what that means is that when the reverse reaction takes place Energy's taken in and the temperature of the system decreases now I should point out that every versal reaction is different some are exothermic in the forward direction and some are exothermic in the reverse direction in the exam you'll be given all the information that you need so the question is what happens if we increase the temperature of this system well as we said before if we make any changes to a system at equilibrium then the system counteracts the change so if we increase the temperature of this system then the equilibrium shifts to the left to reduce the temperature but because the reverse reaction is endothermic so energies taken in causing the temperature to fall so in this case the amount of no.2 would increase on the amount of n2o4 would decrease so what would happen if we decrease the temperature of this system in this case the equilibrium shifts to the right to increase the temperature and that's because the forward reaction is exothermic so energy is released cause the temperature to increase so in this case the amount of n2o4 would increase and the amount of no2 would decrease remember your fun plenty of questions on the effective temperature on reversible reactions in my vision workbook and you can get that by clicking on the link above okay so hopefully now you should be able to describe the effect of changing the temperature on a reversible reaction our equilibrium [Music]