3.1.5 kinetics Flashcards
define activation energy
the minimum amount of energy required for a chemical reaction to take place
explain why most collisions do not lead to a reaction
only a small number of collisions have energy higher than or equal to the activation energy
define rate of reaction
a measure of the change in concentration of a substance per unit time
why does a small increase in temperature results in a large effect on the rate?
a small temperature rise results in significantly more molecules with energy higher than or equal to the activation energy
on a maxwell-boltzmann curve what does the area underneath the distribution curve represent?
the total number of molecules present
state why the distribution curve starts at the origin
because there are no particles with no energy at all
what is the effect of increasing concentration and pressure on rate of reaction?
a higher concentration/ pressure means there are more particles in the same volume
this means the frequency of collisions increases
what are the 2 types of catalyst?
heterogeneous: different phase to the reactants
homogeneous : same phase to the reactants
define catalyst
a substance that increases the rate of a chemical reaction without being changed in chemical composition or amount
how do catalysts work?
providing an alternative reaction route of lower activation energy
