Effect of temperature: Even though chemical adsorption is an
exothermic process, it does not occur slowly at lower temperature due to high
kinetic energy barrier. Hence, like most chemical changes, the extent of
chemisorption increases with increase in temperature up to certain limit and
then after that it starts decreasing. It is also observed that, in some cases,
physisorption of a gas adsorbed at low temperature may change into
chemisorption at a high temperatures.