CHEM 191 Lecture 14

Question 1

how can we show that a reaction is first order

Answer 1

plot ln[A] versus t - if it’s linear then the reaction is first order - the slope is -k and the y int is ln[A]0

Question 2

what is half life

Answer 2

the time taken for [reactant] to reach 1/2 its initial value

Question 3

what is a reaction intermediate

Answer 3

a species which plats a role in the reaction but which doesn’t appear in the overall equation because they are either a reactant nor a product

Question 4

what is a reaction mechanism

Answer 4

a series of elementary reactions that describe an overall reaction

Question 5

when is writing rate laws using stoichiometric coefficients allowed

Answer 5

for elementary reactions

Question 6

can we prove a reaction mechanism

Answer 6

no we can only collect evidence to support a reaction mechanism - we say that the experimental rate law is consistent with the predicted rate law

Question 7

what is the rate determining step

Answer 7

the elementary step in a reaction mechanism that is considered slower than any other step which controls the overall rate of reaction