The rate and extent of chemical changes

Created by

Chloe Brown

Cards (20)

what is the rate of reaction
how quickly reactants in a reaction turn into products
2 equations for rate of reaction
rate = amount of reactant used / time
rate = amount of product made / time
gradient = rate of reaction
change in y / change in x
what are the 4 factors effecting rate of reaction
temp
catalyst
pressure (gas)
surface area (solid)
how does temp increase rate of reaction
increases kinetic energy —> increases collision frequency —> more chance of sucsessful collisions
how does catalysts increase rate of reaction
reduces activation energy —> increased successful collisions
how does pressure increase rate of reaction
increase concentration —> increase collision frequency
how does surface area increase rate of reaction
increase surface area —> increase collision frequency
describe a graph showing a reversible reaction  
at the start all the reactants are reacting so conc falls. As more products are made it’s conc increases then they meet equilibrium if it’s a closed system
what is a dynamic equilibrium
when at equilibrium both reactions are still happening but there is no overall effect
are reversible reactions endo it exothermic reactions  
reversible reactions are endothermic in one direction and exothermic in the other direction
At equilibrium are reactants and products at equal concentrations  
when a reaction is at equilibrium it doesn’t mean reactants and products are equal
what does it mean when equilibrium lies to the left
concentration of reactants is greater
what does it mean when equilibrium lies to the right
concentration of products is greater
what conditions effect the position of equilibrium
temp
pressure
concentration
does a catalyst effect equilibrium
a catalyst doesn’t affect the position of equilibrium but speeds up reaching equilibrium
what is le chateliers principle
the idea the reversible reactions system counteracts any change to the condition
what happens when we change temp
on increase in temp favours the endothermic reaction and decreases in temperature favours the exothermic reaction
what happens when we change pressure
an increase in pressure favours the reaction making fewer molecules a decrease in pressure favours the direction with more molecules
what happens when we change concentration
if you change conc the reaction will no longer be at equilibrium
increase in conc of reactants the system produces more products
decrease of concentration of products the system produces more reactants