Physical - 1.5 Kinetics Flashcards
Define activation energy
The minimum amount of energy for particles to collide with for a successful reaction to take place.
Define catalyst
A substance that increases the rate of reaction by providing an alternative reaction pathway with a lower activation energy.
Define collision theory
Reactions can only occur when collisions take place between particles having sufficient energy.
Define maxwell-boltzmann distribution
Shows the distribution of the molecular energies in a gas at a constant temperature. The area under the curve indicates the total number of particles present.
Define rate of reaction
The change in concentration of a reactant or product in a given period of time.
How does concentration affect rate of reaction?
If concentration of reactant is increased more particles of that reactant are present. Which leads to more successful collisions between reactant particles in a given period of time. This causes the rate of reaction to increase.
How does pressure affect rate of reaction?
If pressure of a gaseous reaction system is increased. The particles are forced closer together which leads to more successful collisions between reactant particles in a given period of time. This causes the rate of reaction to increase.
How does temperature affect the rate of reaction?
If temperature is increased the particles gain energy and more faster which leads to more successful collisions between reactant particles in a given period. This causes the rate of reaction to increase.
How does the surface area of solid reactants affect the rate of reaction?
Increasing the surface area of solid reactants increases the exposed surface of the reactants, this increases the number of successful collisions in a given period of time. This causes the rate of reaction to increase.
How does a catalyst affect the rate of reaction?
Increases the rate of reaction without being used up. A catalyst works by providing an alternative reaction pathway of lower activation energy. More collisions are successful in a given period of time, so rate of reaction increases.
How does the Maxwell Boltzmann distribution change at different temperatures?
Lower temperature distributions are moved left and the peak is higher.
Higher temperature distributions are moved to the right and the peak is lower.
How does the Maxwell Boltzmann distribution change at different concentrations?
As there are more total reactant molecules at the same temperature, the overall area under the curve increases. This increases the number of reactant molecules which have enough energy to undergo a successful reaction, higher rate of reaction.
