10.1 reaction rates module 3 Flashcards
what does the rate of a chemical reaction measures?
how fast a reactant is being used up or how fast a product is formed
what is the rate of reaction the same as?
the change in concentration of a reactant or a product in a given time
rate of reaction=??
change of concentration/ time
units of rate of reaction equation
change in concentration= mol dm-3
time= seconds
rate of reaction= mol dm-3 s-1
when is rate of reaction fastest?
at the start of the reaction as each reactant is at it’s highest concentration
why does the rate of reaction slow down as the reaction goes on?
reactants are used up and their concentrations decrease
what happens when one of the reactants has been completely used up?
concentration stops changing and the rate of reaction is zero
how do you work out the rate of reaction from a graph?
draw a tangent
change in y/ change in x
what are the factors that change the rate of a chemical reaction?
concentration or pressure
temperature
use of a catalyst
surface area of solid reactants
what is collision theory?
two reacting particles must collide for a reaction to occur
how does surface area affect rate of reaction?
larger the surface area
more particles exposed
frequency of collisions increases
how does temperature affect the rate of reaction?
higher KE, colliding more and colliding with more energy
how does concentration/ pressure affect the rate of reaction?
particles are more crowded
more particles in the same volume
closer together
collide more frequently
define catalyst
provide an alternative pathway using a lower activation energy
what does an effective collision lead to?
a chemical reaction
what makes an effective collision?
particles collide with the correct orientation
particles have sufficient energy to overcome the activation energy barrier of the reaction
how do you follow the progress of the reaction?
monitoring the removal of a reactant which is the decrease in concentration
following the formation of a product which is the increase in concentration
how do you measure the volume of gas produced?
use gas syringe
water filled tube, gas displaces the water in the tube
mass balance
