Arrhenius

Question 1

What is the ‘Arrhenius’ equation?

Answer 1

K = Ae^ -Ea/RT

K = rate constant.
A = pre-exponential factor.
Ea = activation energy.
R = gas constant.
T = temperature.

Question 2

What does the exponential factor e ^ -Ea/RT represent?

Answer 2

• The proportion of molecules that exceed Ea and that have sufficient energy for a reaction to take place.

Question 3

What does the pre-exponential term ‘A’ (frequency factor) represent?

Answer 3

• It takes into account the frequency of collisions with the correct orientation.

Question 4

What is the logarithmic form of the Arrhenius equation?

Answer 4

• ln k = - Ea/RT + ln A.

Question 5

Why is a plot of ln k vs 1/T useful?

Answer 5

• It gives a straight line graph.

Y = M X + C
Ln k = -Ea/R 1/T + Ln A

• Gradient (m) = -Ea/R.
• Y intecept = ln A.