5A - Rates definitions

Question 1

Rate of reaction

Units?

Answer 1

The change in concentration of a reactant/ product in a given time

Units = moldm^-3S^-1

Question 2

Order of reaction

Answer 2

The power to which the concentration of a reaction is raised to in the rate equation.

It’s always 0,1 or 2

Question 3

Rate contstant (k)

Answer 3

The constant proportionality between the rate of the reaction and the concentration of reactants

Question 4

Overall order

Answer 4

Sum of the individual orders of reactant sin the rate equation

Question 5

Rate equation = ?

Answer 5

For the reaction: aA + bB ⇌ cC + dD

Rate = k[A]^x[B]^y

Units = moldm^-3S^-1

NOTE:

Rate directly proportaionl to [A]^x

Rate directly proportaionl to [B]^y

Question 6

Half life

Answer 6

Time taken for the concentration of a reactant to decrease by half

Question 7

Initial rate of reaction

Answer 7

The change in concentration of a reactant or product per unit time at t = 0

Question 8

k = ?

When you know the half life

Answer 8

k = ln2 / t_1/2

Where t_1/2 = half life

NOTE:

This only works if you have a 1st order reaction overall

Question 9

Rate determining step

Answer 9

The slowest step in the mechanism

Question 10

Arrhenius equation = ?

• Normal form (on data sheet)
• Logarithmic form (not given)

Answer 10