CI - Half-lives and rate equations Flashcards
What is a half-life?
The time taken for a reactant to halve in quantity.
The time it takes for half of the reactant to be used up.
From what graph is it easy to calculate half-lives from?
Concentration-time graphs.
What does t 1/2 mean?
Half-life
What is the symbol for half-life?
t 1/2
What will the half-lives be like in a zero order reaction?
The half-life decreases.
What will the half-lives be like in a first order reaction?
Constant.
What will the half-lives be like in a second order reaction?
The half-life increases.
What do you need to know to write a rate equation?
The order for each reactant.
From what order of reaction can you find the rate constant from the half-lives?
First order reaction.
What is the half-life of a first order reaction independent of?
The concentration.
What does it mean that the half-life of a first order reaction independent of the concentration?
Each half-live will be the same length.
By knowing the half-life of a first order reaction, what equation can be used to work out the rate constant?
k = ln2/t1/2
What are the units for the equation k = ln2/t1/2 for working out rate constant?
no units/s = s^-1
