kinetics

Question 1

For an exothermic reaction, explain why a straight line is not obtained on a rate vs concentration graph.

Answer 1

→ concentration increases = more frequent collisions
→ rate of reaction increases = more heat is given out
→ more heat means that more particles have sufficient energy (Eₐ)

Question 2

State what is meant by the term activation energy.

Answer 2

the minimum energy required for a reaction to start

Question 3

State what is meant by the term rate of reaction

Answer 3

change in concentration in a given time

Question 4

Explain why, at a fixed temperature, the rate of this reaction doubles when the concentration of the hydrochloric acid doubles.

Answer 4

• twice as many HCl particles per given volume
• twice as many particles with E > Eₐ
• twice as many successful collisions

Question 5

Explain why a small increase in temperature has a large effect on the initial rate of a reaction.

Answer 5

• it results in a much higher proportion of molecules
• with energy greater than Eₐ
• compared to a small increase in concentration

Question 6

Explain how a catalyst works.

Answer 6

→ lowers the activation energy

→ by providing alternative reaction pathway

Question 7

Explain what must happen for a reaction to occur between molecules of two different gases.

Answer 7

must collide with sufficient energy