c5 - rates of reaction Flashcards
equilibrium
a state in a reaction where the rate of the forward reaction is equal to the rate of the reverse reaction
le chatelier’s principle
if a system is at equilibrium and a change is made to any of the conditions then the system responds to counteract that change
dynamic equilibrium
where forward and backward reactions are happening at the same rate
effect of increasing temperature on equilibrium
shifts equilibrium to favour endothermic reaction
effect of decreasing temperature on equilibrium
shifts equilibrium to favour the exothermic reaction
effect of increase of concentration of reactants in a reaction (3)
equilibrium shifts to right to make more product bringing it back to equilibrium
effect of increasing concentration of products in a reaction (3)
equilibrium shifts to left to make more product bringing it back to equilibrium
effect of increasing pressure of gas in reaction
equilibrium shifts to favour the reaction with less particles as this will decrease the pressure
effect of decreasing pressure of gas in a reaction
equilibrium shifts to favour the reaction with most particles as this will decrease the pressure
activation energy
minimum energy required for a chemical reaction to take place
collision theory
the theory states that for a chemical reaction to happen particles must collide with sufficient energy
frequency
the amount of times something happens in a second
concentration
number of particles in a given volume
factors effecting rate of reaction
- temperature
- pressure
- concentration of solution
- surface area
- presence of a catalyst
in reference to collision theory
what two things does rate of reaction depend on
- frequency of collisions between particles
- the energy with which the particles collide
what is the relationship between concentration and rate of reaction
directly proportional , if u double concentration u double the rate
collision theory in reference to temperature (3)
when u increse temperature the particles will move faster causing more frequent succesful collisions between particles. speed also causes particles to collide with more energy meaning activation energy is likely exceeded
collision theory in reference to concentration
if concentration is incresed there are more particles in a given volume causing more frequent succesful collisions causing rate of reaction to increase as it is directly proportional to concentration
collision theory
collision theory in reference to surface area
when you increase the surface area of a solid u increase the number of particles available for collision causing there to be more frequent succesful collisions increasing the rate of reaction
collision theory in reference to pressure
when pressure is increased in a gaseous reaction the rate will increase as there are more particles in a given volume of gas causing more frequent successful collisions
mean rate of reaction formula
quantity of reactant used / time taken
or
quantity of product formed / time taken
units for rate of reaction
The units of rate of reaction may be given as g/s, cm3/s or mol/s.
how do you calculate specific rate of reaction
Draw a tangent at the specific time and calculate the gradient.
define reversible reactions in terms of energy changes
If a reversible reaction is exothermic in one direction, it is endothermic in the opposite direction. The same amount of energy is transferred in each case.
