Rate Equations

explain why doubling the temp has a much greater effect on the RoR than doubling the conc of E in Rate=k[E]

• reaction occurs when molecules have energy greater or equal to Ea

• doubling temp causes many more molecules to have this energy

• whereas doubling con only doubles the number of that energy

explain how a graph can confirm that the rate equation is Rate=k[A]

a straight line AND through the origin

suggest why using a large excess of a salt means that the rate is only affected by changing the conc of something else not the salt

the surface area stays the same

Suggest why a loose cotton wool plug is placed in a flask instead of

-leaving the flask open

-inserting a bung

• avoid slashing

• to allow gas to escape

what is needed to figure out the rate determining step from the rate equation

a step that contains all the species in the rate equation

explain how a graph van show that reaction is zero-order

• graph is a straight line

• so RoR doesn’t change as the conc of the other reactants change

deduce the overall effect on the RoR when the conc of both L and M are halved in Rate=k[L][M]2

multiplied by 1/8 (2 to the power 3)