6.6 The Arrhenius Equation

Question 1

What does the Arrhenius equation show?

Answer 1

The variation of the rate constant with temperature, as temperature increase the rate constant increase exponentially.

Question 2

What is the Arrhenius equation?

Answer 2

k = Ae^(-Ea/RT)
A is the frequency factor
R is the gas constant
T is the temperature in K

Question 3

What is A in this equation?

Answer 3

The frequency factor or pre exponential factor and is related to the orientation of the collisions and the frequency of collisions. A is essentially a constant for a particular reaction as temperature varies. Generally the more complex the molecules the smaller the value of A since fewer collision with energy greater than or equal to the activation energy will result in a reaction because it is less likely that complex molecules will collide in the correct orientation compared to simples molecules.

Question 4

What is the other form of the Arrhenius equation?

Answer 4

lnk = -Ea/R x 1/T + lnA

This form of the equation can be used to work out a value for the activation energy.