kinetics Flashcards
what is rate of reaction
the change of concentration of reactant or product per unit time
what is rate
amount of reactant used/product made
over time
what is collision theory
for a reaction to occur the particles must collide in the right direction and they must also have a minimum amount of kinetic energy
what is activation energy
the minimum amount of energy required for a reaction to occur
what is the peak on a maxwell boltzmann distribution graph
the most likely energy of a particle in a sample
where is the mean energy on maxwell boltzmann distribution graph
right from the most likely energy
factors of maxwell boltzmann distribution graph
starts at 0,0 as no particles have no kinetic energy
area under curve is equal to total number of molecules
y axis = number of molecules
x axis = kinetic energy
how does temperature affect rate of reaction
particles have on average more kinetic energy when heated
larger proportion of particles will have energy greater than the activation energy
temperature on maxwell boltzmann distribution
curve shifts to the right
peak is lower
area under curve is the same
area under curve beyond Ea increases
why do we get a faster rate of reaction when temperature is increased
particles move around more at higher temperatures
there are more frequent successful collisions which are more energetic
why do we get a faster rate of reaction when pressure or concentration is increased
particles are closer together so collide more often
there are more frequent successful collisions and so higher chance of a reaction
what is a catalyst
a substance than increases the rate of reaction by providing an alternative pathway that has a lower activation energy, it remains chemically unchanged
how do catalysts affect industry
1) lowers temperature needed = less money spent on energy and less co2 produced
2) speed up reaction so faster production
3) change properties of a product
4) less waste produced as catalysts allow reactions with better atom economies
what is a heterogeneous catalyst
in a different phase (state) from the reactants
what happens when surface area is increased with heterogeneous catalyst
increase rate of reaction as more particles can react with catalyst at the same time
