Reaction Mechanisms

Question 1

What are intermediates?

Answer 1

 An intermediate is a chemical species involved in a mechanism that does not appear in the overall reaction

Question 2

What is a reaction mechanism?

Answer 2

o The steps involved in a chemical reaction make up way we call a mechanism
 What bonds break, what intermediate species are formed, what is the role of a catalyst

Question 3

What is the rate limiting step?

Answer 3

o The rate of the overall reaction is determined by the rate of the slowest step in the mechanism

Question 4

What is a unimolecular reaction?

Answer 4

 Unimolecular steps in a reaction mechanism are elementary steps in which a single molecule does something (typically breaks a bond)

Question 5

What is a bimolecular reaction?

Answer 5

 Elementary reaction steps that involve two reactant species. The two molecules collide and then react.

Question 6

What is the molecularity?

Answer 6

o The molecularity is a way of stating exactly how many molecules are involved in the elementary step

Question 7

Why are almost all elementary steps unimolecular or bimolecular?

Answer 7

o Almost always unimolecular or bimolecular because the chances of having three distinct molecules collide and simultaneously interact is vanishingly small