Chemistry- Reversible Reactions and Equlibrium

what is a reversible reaction

a reaction that can be made to go in either direction depending on the conditions

what does anhydrous mean

without water

is the energy change in the forwards direction is -x, what is it in the backwards direction

equally positive, +x

how do we use anhydrous copper sulphate to test for water

add the sample liquid to the anhydrous copper sulphate, if it turns from white to blue, it is water

what is a sign that a direction of reaction is endothermic

it needs to be heated

what is dynamic equilibrium

when the forwards and backwards rate of reactions are equal in a reversible reaction, so the concentration and amount of each substance doesn’t change

how can dynamic equilibrium be reached

when a reversible reaction takes place in a closed system

what is meant when we say the equilibrium ‘lies to the left’

that at equilibrium, there is more A (left) than B (right)

how can we tell when dynamic equilibrium has been reached

concentration stays constant, shows by 2 parallel straight lines

what is meant by a closed system

no substances are added/lost from the system

state Le Chatelier’s principle

the position of the equilibrium will shift to oppose an external change

what effect does increasing the concentration of A (left) have

the equilibrium will shift to the right

what effect does decreasing the concentration of A (left) have

the equilibrium will shift to the left

what effect does increasing pressure have

the equilibrium will shifts to the side with fewer moles (use big numbers)

what effect does decreasing pressure do

the equilibrium will shift to the side with more moles

what effect does pressure have if the amount of moles is balanced

it has no effect

if we increase pressure what else increases

the rate of reaction

how can increased pressure increase yield

whichever direction the equilibrium shifts in, more of this will be made

what needs to be done to carry out thermal decomposition

heating the substance

what effect does increasing temperature have

it shifts the equilibrium in the endothermic direction

what effect does decreasing temperature have

the equilibrium will shift in the exothermic direction

how can we tell if a forwards reaction is exothermic

\-it will have a negative energy change (exes negative vibes)

what does a positive energy change indicate

an endothermic reaction

what 3 things must be referenced when temperature effect on equilibrium

\-direction

\-exo/endothermic?

\-change opposed

how can we tell which direction is exo/endothermic if we don’t know energy change

if the substances in the reaction are coloured, we could observe the colour change caused by increasing temperature

\-ie, if forwards reaction product was blue, and increased temp made the substance more blue, then the forwrdas reaction is endothermic

explain how a catalyst increases the rate of reaction

it provides an alternative reaction route with a lower activation energy