The effect of temperature on the rate constant

Question 1

the two reasons for why temperature increases the rate of reaction are:

Answer 1

• incerases the fraction of molecules with the required activaiton energy
• overall increase in the frequency of collisions between reacting particles

Question 2

the Arrhenius equation is :

Answer 2

k = Ae ( - Ea / RT )

A: a constant known as the pre-exponential factor, a measure of the rate at which collisions occur regardless of their energy, but involving other factors such as orientation during collisions
Ea: activation energy of the reaction ( J mol-1)
R: gas constant (8.31 J mol-1 K-1)
T: absolute temperature in Kelvin (K)
e: 2.718

Question 3

the natural logarithm of the Arrhenius equation is

Answer 3

Ea
In k = - —- + In A
R T

Question 4

if a graph of In K is plotted against 1 /T, a ………line is obtained with a gradient of ………….

Answer 4

straight line

gradient of - Ea / R

Question 5

on a graph where In K is plotted against 1 /T, In A is

Answer 5

the intercept with the y axis

Question 6

when the temperature is increased, the value of InK ……………

Answer 6

incerases too

Question 7

when the temperature increases, the value of 1/T………..

Answer 7

decrease

Question 8

the factor e-^(EA / RT) represents

Answer 8

the fraction of collisions that have energy equal to or greater than the activation energy, Ea

Question 9

reactions with a large Ea are…….(speed of the reaction),

but the rate……………….rapidly with temperatrue

Answer 9

slow

rate increases rapidly with temp

Question 10

reactions with a small Ea are….(speed of the reaction) but the rate…………..with an increase in temperature

Answer 10

fast

but the rate does not increase as rapidly with temp