Physical: kinetics Flashcards
state what collision theory is
for a chemical reaction to take place the particles need to collide with each other in the correct orientation and with enough activation energy
state what activation energy is
minimum amount of energy needed for a reaction to take place
which direction is exo and endo on diagrams
In exothermic reactions the reactants are higher in energy than the products
In endothermic reactions the reactants are lower in energy than the products
explain what a catalyst does
increases rate of reaction without being used up by providing an alternate pathway with lower activation energy
calculate the rate of reaction
rate of reaction= change in product or reactants (moldm-3) / time (s)
what even is a Maxwell-Boltzmann graph
Maxwell-Boltzmann distribution curve is a graph that shows the distribution of energies at a certain temperature, and where there is energy energy for effective collisions for the chemical reaction to take place
explain the effect of increase in temperature on a reaction, and the effect on a MB graph
increase in temp causes particles to have more kinetic energy leading to more frequent collisions, increasing the chance of successful collisions with enough activation energies for the reaction to take place
on a MB graph the curve flattens and the peak shifts right, so more particles have enough Ea
explain the effect of concentration of rate of reaction
the more concentrated a solution is the more particles in a given volume this increases the collision frequency increasing rate of reaction
explain the effect of pressure on rate of reaction
increase in pressure decreases the space available for the particles this increase the collision frequency so increases rate of reaction
explain that catalysts can be divided into two types:
Homogeneous catalysts
Heterogeneous catalysts
Homogeneous means that the catalyst is in the same phase as the reactants
For example, the reactants and the catalysts are all in solution
Heterogeneous means that the catalyst is in a different phase to the reactants
For example, the reactants are gases but the catalyst used is a solid
define dynamic equilibrium
dynamic equilibrium the rate of the forward reaction is the same as the rate of the backward reaction in a closed system, and the concentrations of the reactants and products is constant
define Le Chatelier’s principle
Le Chatelier’s principle says that if a change is made to a system in dynamic equilibrium, the position of the equilibrium moves to counteract this change
explain effect on increasing concetration
equilibrium shifts to the right to reduce the effect of the increase of a reactant
explain the effect on decreasing concetration
equilibrium shifts to the left to reduce the effect of a decrease in a reactant
explain the effect of increasing pressure
equilibriuum shifts to the side with less moles to decrease the pressure
