collision theory and reaction rates Flashcards
what is a chemical reaction
a chemical reaction is when existing bonds are broken and new one are created in the process
what is collision theory
For particles to react, three things need to happen:
Particles must collide.
The collisions must have enough energy to break old bonds and form new ones.
Particles must collide in the correct orientation for particles to rearrange and make new compounds.
when does a chemical reaction occur
a chemical reaction sometime occur when substances are mixed and particles collide
does every collision result in a reaction
no
what is reaction rate
reaction rate is how fast the reaction occurs
what are the five factors that control the rate of chemical reactions
Surface area of reactants
Temperature of reactants
Concentration of reactants
Action of a catalyst
Nature of reactants
what is reaction rate
reaction rate is how fast the reaction occur
how does surface area of reactants affect the reaction rate
The greater the surface area exposed in a reaction, the greater the number of collisions.
More collisions means there is a greater likelihood of a successful collision – so faster reaction rate.
how does temperature of reactants affect the reaction rate
Increasing the temperature of the reactants causes an increase in the average kinetic energy of the particles.
This affects the reaction rate in two ways:
More particles have enough energy to react.
More collisions occur since the reactant particles are moving faster.
how does concentration of reactants affect the reaction rate
If the concentration of reactants is increased, there will be more frequent collisions between the particles.
If the particles collide more often, there will be a greater likelihood of a successful collision.
how does the use of catalyst affect the reaction rate
A catalyst is a substance that increases the reaction rate, but is not consumed in the reaction.
A catalyst provides the reactants with an alternative pathway that needs less energy.
More collisions will have enough energy to react.
how does the nature of reactants affect the reaction rate
The state of matter of the reactants can affect the speed of a reaction.
Liquids will often react more quickly than solids.
The particles in the liquid are able to move more freely than those in a solid, colliding more frequently.
Reactions involving substances dissolved in a solution will be fast.
