Unit 1.3 Reaction Kinetics

Question 1

What does Reaction Kinetics study?

Answer 1

The reaction rates, which allow for an understanding of how reaction work and the behaviour of molecules while reacting

Question 2

How can a reaction mechanism be deduced

Answer 2

Only from experiment, cannot be done from a balanced chemical reaction

Question 3

What is a Reaction Mechanism?

Answer 3

The series of steps a reaction takes

Question 4

What is an Elementary Reaction?

Answer 4

A reaction that occurs within a single step

Question 5

What is a Composite Reaction?

Answer 5

A reaction that occurs over several steps, the balanced equation represents the sum of the steps

Question 6

What is a Zero Order Reaction?

Answer 6

When the concentration of a reactant is doubled and there is no change in reaction rate

Question 7

What is a First Order Reaction?

Answer 7

When the concentration of a reactant in doubled, and in response so is the reaction rate

Question 8

What is a Second Order Reaction?

Answer 8

When the reactant is doubled and the reaction rate increased four times in response

Question 9

How do you calculate the overall order of a reaction?

Answer 9

The overall order of the reaction is the sum of the orders for the reaction

Question 10

What is Reaction Order?

Answer 10

The relationship between the conc of a reactant and the rate of reaction

Question 11

Draw a Zero Order graph when time and concentration is increased:

Answer 11

-As time increases, the conc decreases (straight line down)
-As conc increases the rate stays the same (straight flat line)

Question 12

Draw a First Order graph when time and concentration increases:

Answer 12

-As time increases the conc decreases (curve down)
-As conc increases rate increases (straight line up)

Question 13

Draw a Second Order graph in response to an increase in time and concentration:

Answer 13

-As time increases the conc decreases (steep then levels off slightly)
-As conc increases the rate increases (not steep to steep)

Question 14

What is the Half-Life of a Reactant?

Answer 14

The time taken for the reactant concentration to decrease to one-half of its initial value

Question 15

What 3 steps are followed when suggesting a Reaction Mechanism for a Composite Reaction?

Answer 15

1. The balanced equation for the reaction is a sum of the steps
   2.The steps are reasonable (must be able to happen)
   3.The mechanism is consistent with the rate law and other experimental observations

Question 16

How is a Reaction Mechanism proven?

Answer 16

It cannot be proven just supported

Question 17

Is the Rate Determining Step faster or slower than other steps?

Answer 17

Slower as it controls the overall rate of reaction