kinetics 1 p2 Flashcards
rate equation
rate = change in conc / time
unit for rate of reaction
mol dm-3 s-1
what must particles do in order to react?
collide with sufficient energy (activation energy) and the correct orientation
do most collisions result in reaction?
no
what factors affect rate of reaction?
temp, pressure, conc, surface area, catalyst
how does increasing temp effect rate of reaction?
increased temp = increased rate of reaction
higher proportion of particles have energy greater than the activation energy —> more successful collisions per second
how does increasing conc/pressure effect rate of reaction?
increased conc/pressure = increased rate of reaction
more particles in a given volume —> more frequent collisions —> increased rate
what variables in an experiment can be monitored to calculate the rate of reaction?
conc, gas volume of products, mass of substances formed
how do you calculate rate from a conc time graph?
(time on x axis, conc on y axis)
draw a tangent
work out gradient
what is a catalyst?
substance which increases the rate of reaction but is not used up in the reaction
how do catalysts work and how do they increase the rate of reaction?
provide an alternative reaction pathway (with a lower activation energy)
due to the lower activation energy, more particles have energy > activation energy, so more frequent successful collisions, so increased rate
what does homogeneous catalyst mean?
catalyst in the same phase as the reactants
what does heterogeneous catalyst mean?
catalyst used in the reaction is in different phase to the reactants
what are the economic benefits of using a catalyst in industrial reactions?
catalysed reactions occur at lower temperatures so less fuel needed
could lead to higher atom economy so fewer raw materials needed and less waste products produced
activation energy
minimum energy particles must collide with for a reaction to occur
