Rates of Reaction and collision Theory Flashcards
The speed of a reaction depends of 4 factors:
. temperature
. concentration of the reactants (or pressure if the reactants are
gases)
. the presence of a catalyst
. if one of the reactants is a solid, the surface area
when the graph is levelled out, what has happened to the reaction
there are no more reactant particles reacting, the reaction has stopped (speed = 0).
what’s Rate of Reaction
the speed at which a reaction takes place
what are the three main methods of measuring the Rate of Reactions ( describe them ).
CHANGE IN MASS - recording the loss of mass divided by time gives an accurate rate measurement .
VOLUME OF GAS FORMED ( gas syringe ) - recording the volume of gas divided by time gives and accurate rate measurement.
FORMATION OF A PRECIPITATE - recording decrease of light intensity divided time gives an accurate rate measurement.
what is a gas syringe used for ?
a gas syringe is used to collect the gas as it is produced during the reaction.
what must reaction particles do for reaction to take place ?
they must collide
A successful collision happens when the reacting particles have ________ ________
sufficient energy
what is ‘Activation Energy’ ?
Activation energy is the minimum energy reacting particles must have when they collide for the reaction to take place.
what happens when you increase the Rate of Reaction ?
increasing the Rate of Reaction increases the chance / frequency of successful collisions
There are 4 ways of changing the rate of reaction
- temperature
- concentration
- surface area
- catalyst
increasing the temperature makes the particles move FASTER or SLOWER / gives MORE or LESS kinetic energy .
MORE KINETIC ENERGY => FASTER
Do you have a faster Rate of Reaction if you increase the chance of successful collision
Yes
Increasing the concentration increases the number of ________ _________
Reacting particles in one area
At a higher pressure, is there MORE or LESS reacting particles in the same space
MORE
Breaking a solid into smaller pieces increases what
surface area
having a larger surface area provides more space for the reacting particles to collide =>
this INCREASES THE CHANCE of successful collisions - so a FASTER RATE OF REACTION
adding a catalyst to the reaction does what ?
lowers the activation energy of the reaction
when reactant particles collide, what do they form?
products
a catalyst is a substance that SPEEDS UP or SLOWS DOWN a reaction
SPEEDS UP
does a catalyst get used up ( consumed ) when added to a reaction
No ( remains unchanged after reaction )
By lowering the activation energy ( adding catalyst ) does it have a FASTER or SLOWER Rate of Reaction, that increases the chance of successful collisions
FASTER
key point that FASTER REACTION(s) might have then others.
- higher temp
- higher concentration
- larger surface area
- might have catalyst
key point that SLOWER REACTION(s) might have then others.
- lower temp
- lower concentration
- smaller surface area
- might not have catalyst
A reaction can be followed by measuring the amount of _______formed or by measuring the amount of reactant used up.
products
rate can be defined as -
rate of reaction =amount of reactant used or product formed
_____________________________________________
time
