chemistry - reaction rates

what does collision theory state

Collision theory states that for a chemical reaction to occur, reactants must collide, must collide with sufficient energy and must collide with proper orientation.

what are the four factors that affect reaction rate

temperature, concentration/pressure, surface area(agitation), catalyst

affect temperature has on reaction rate

As temperature increases, the average kinetic energy of the particles increases, so a larger percentage of collisions have enough energy to meet the activation energy. Also the particles move faster increasing the rate of collisions. Both of these effects increase the rate of successful collisions, increasing the reaction rate.

Affect of concentration/pressure on reaction rate

Increasing the concentration/pressure decreases the distance between particles, increasing the rate of collisions, increasing the rate of successful collisions, increasing the reaction rate.

Affect of surface area on reaction rate

Increasing the surface area exposes more reactant particles to each other, increasing the rate of collisions, increasing the rate of successful collisions, increasing reaction rate.

Affect of catalysts on reaction rate

Adding a catalyst provides an alternate reaction pathway with lower activation energy, so a larger percentage of collisions have enough energy to meet the activation energy, this increases the rate of successful collisions, increasing the reaction rate.

Describe the function of a catalytic converter in a car exhaust

convert unburnt fuel molecules (and CO) to CO₂ and H₂O

convert nitrous oxides to N₂

makes the exhaust safer for people and the environment