17.1: Reaction Ratesdhsmsp.weebly.com/uploads/1/3/7/3/13735507/factors... · Factors Affecting...
Transcript of 17.1: Reaction Ratesdhsmsp.weebly.com/uploads/1/3/7/3/13735507/factors... · Factors Affecting...
Factors Affecting Reaction Rates
Speed of chemical reactions
Rate at which: reactants are used OR products are formed
Concentration
Surface Area
Pressure (gases only)
Temperature
Catalyst
When the reactants are concentrated, more chance of colliding and therefore making more products
Molarity
When there are many molecules of each reactant, the collisions happen often and the reaction is quick
When few atoms are left, the collisions happen less often
and the reaction slows down and eventually ends
Large block of reactantsMost atoms trapped inside, aren’t reacting
Smaller pieces, increase surface area, leaving more reactants exposed to react
As Pressure increases, volume decreases (boyle’s law)
Increasing pressure causes particles to collide more oftenTherefore increasing rate
of reaction
When two particles collide they require Activation Energy to react.Too Slow, so they bounced offLets speed it up a little
Finally these particles had enough combined energy to react!
Still not enough combined energy
Increases speed of particles, increases energy of particles to collide and number of collisions
Speeds up rate of reaction, without changing reaction
Lowers activation energy
Help rearrange bonds to form products
More particles are allowed to react
Concentration: concentration of reactants, faster rate of reaction
Surface Area: SA (smaller pieces), faster rate of reaction
Pressure (gases only): P, more collisions, faster rate of reaction
Temperature: T, faster particles & more collisions, faster rate of reaction
Catalyst: Presence of catalyst, faster rate of reaction, doesn’t change
reaction, lowers activation energy