collision theory + reaction profiles. Flashcards
what is kinetics?
The study of how fast reactions are.
describe how kinetic energy differs in solids, liquids and gases. and explain each one of them.
solids: Not much kinetic energy, because the particles are constantly vibrating, but can’t move around.
liquids: some kinetic energy, they can move around each other, but not as spaced apart as gases.
gases: Very high kinetic energy, they can move around each other, and they are very spaced apart.
what are the two main factors which affect successful collisions?
Activation energy and orientation of molecules.
what is meant by activation energy, and what is its symbol?
Activation energy is the minimum ammount of energy required to form a successful collision between particles.
what is meant by orientation of molecules?
particles have to be properly orientated in order to react.
define rate of reaction.
The amount of product, that is made in a reaction, per unit of time.
what are the two factors by which Arte of reaction is determined by?
proportion of collisions that are successful and frequency of successful collisions.
what are the 4 factors that affect rate of reaction?
temperature, concentration, pressure and surface area.
explain how temperature affects rates of reaction.
Increasing the temperature, means that particles have more kinetic energy.
This therefor means that the proportion of successful collisions will increase, because more particles will have the required activation energy.
This also means that the particles will move faster, which means a higher frequency of successful collisions.
explain how pressure increases the rate of reaction.
It only affects the rate of reaction, when one or more reactants are gases.
the pressure is the number of collisions between the particles and the walls of the container its in.
Increasing the pressure, means that there is a larger number of particles in a given volume, which means there will be a higher frequency of successful collisions in a given period of time.
What is a reaction profile?
A reaction profile is a diagram used in kinetics, In order to show the energy changes, as a reaction progresses.
Explain how concentration increases the rate of reaction.
Concentration is a measure of how much solute, is dissolved per volume of solvent.
Increasing the concentration, means that there are more numbers of solute per volume of solvent.
This means that collisions will happen more frequently, thus more successful collisions in a given time period.
explain how surface area increases rate of reaction.
Only in solid reactants.
The larger the surface area, the higher the frequency of successful collisions in a given period of time.
what is an endothermic reaction?
Takes in heat energy from the surroundings, in to the reaction system.
What is an exothermic reaction?
Gives out heat from the reaction system, to the sorroundings.
