speed of reaction
measuring speed of a chemical reaction
Δ in temperature against time
collision theory
factors that affect the speed of reaction
during a chemical reaction
temperature
surface area
concentration
pressure
Δ in pH against time
catalyst
Δ in mass/volume against time
formation of precipitate against time
↑ temperature leads to ↑ rate of reaction
Δ in colour against time
↑ concentration leads to ↑ rate of reaction
↑ surface area of a solid leads to ↑ rate of reaction
adding a catalyst leads to ↑ rate of reaction
the reacting chemical molecules must collide with each other
↑ temperature leads to ↑ kinetic energy of particles leads to ↑ frequency of particles colliding leads to ↑ chance of reaction taking place
the reacting chemical molecules must collide with sufficient energy, equal to or greater than the reaction's activation energy
molecules move around randomly (kinetic energy)
common catalysts used
Iron [Fe]
Nickel [Ni]
Vanadium(V)Oxide [V2O5]
manufacture of ammonia (harber process)
↑ frequency of effective collisions leads to ↑ rate of reaction
manufacture of margarine
manufacture of sulfuric acid (contact process)
↑ concentration of solution means ↑ particles it contains per unit volume. frequency of collision ↑ since particles are closer together
↓ activation energy of reaction by allowing the reaction to take place via an alternative pathway
↑ frequency of effective collisions leads to ↑ rate of reaction
↓ activation energy leads to ↑ collisions between particles will have sufficient energy for a reaction to take place
↑ pressure of gas leads to ↑ rate of reaction
if the energy is sufficient (or greater) the collision caused the chemical bonds to break
↑ pressure of gas forces the particles closer together, which leads to ↑ frequency of collision
eventually colliding
↑ frequency of effective collisions leads to ↑ of rate of reaction
↑ frequency of effective collisions leads to ↑ rate of reaction
↑ frequency of effective collisions leads to ↑ rate of reaction
↑ surface of a solid reagent leads to ↑ area over which collisions between the chemicals take place leads to frequency of collision
enzymes
now that the original bonds are broken, new chemical bonds can be formed
biological catalysts that ↑ speed of reaction
very sensitive to temperature and pH
resulting in new chemical products
reaction falls rapidly at temperatures ↑ 40°C
a catalyst reduces the activation energy of a reaction by allowing the reaction to take place via an alternative pathway
only functions over a narrow pH range