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Define rate

change in concentration of reactant or product with time

how to work out rate of reaction and units

change in concentration of reactant or product / time taken for the change to take place
moldm^-3 s^-1

When is the highest rate of reaction

at t=0
rate is highest when gradient is steepest

state and explain how the rate of reaction changes with time

*the rate of reaction decreases with time
*concentration of HCl(aq) decreases with time
*there are less particles per unit volume
*there are less successful collisions per unit time

how to work out the overall order of a reaction

add the orders
e.g. add the powers in the rate equation

what is the rate equation

Rate = k[A]^m[B]^n where m and n are the orders with respect to reactants A and B respectively, [A] and [B] are the concentrations of A and B respectively and k is the rate constant

what are the units of concentration

mol dm^-3

what are the units of rate

mol dm^-3 s^-1

what is the relationship between first order k and half life?

k = ln2/half life

what is the order of a reactant if it has no effect on rate

zero order

what is the link between the rate equation and the RDS

rate equation only includes species involved in the RDS

what is significant about half lives in first order reactions

constant half life

what is the slowest step in a mechanism called

rate determining step

what is the order of a reactant if doubling the conc leads to rate x4

second order

what is the order of a reactant if doubling the conc doubles the rate

first order

which equation links the rate constant and the activation energy

Arrhenius equation

what is meant by the half life of a reactant

the time taken for the concentration of a reaction to decrease to half its original value

what do the rate against concentration graphs look like for the zero, first and second orders

what do the concentration against time graphs look like for the zero, first and second order

zero order - half life decreases with time
first order- constant half life
second order - half life increases with time