LT#6: Reaction Mechanisms

Question 1

Define Reaction Mechanism

Answer 1

Series of steps that make up a more complex overall chemical reaction

Question 2

Why do Mechanisms occur?

Answer 2

Having more than 2 particles simultaneously collide at the proper orientation, all with the correct activation energy is extremely unlikely.

Question 3

Define Reaction Intermediate

Answer 3

Chemicals that are made in one step, used in another, and don’t show up in the overall equation.

Question 4

Describe the first test of reasonability for a reaction mechanism.

Answer 4

The steps must algebraically add together to give the overall equation.

Question 5

Describe the second test of reasonability for a reaction mechanism.

Answer 5

The proposed steps must have probable collisions.

Uni and bimolecular steps are fine, termolecular steps are rare.

Question 6

Describe the third test of reasonability for a reaction mechanism.

Answer 6

3. The mechanism must support the experimentally determined rate law.

The rate law for the slowest step must match the experimentally determined rate law for the overall reaction.

Question 7

How do you write the rate law for the slowest step in a mechanism?

Answer 7

Use the coefficients in the equation for the slow step as rate exponents.