10- Reaction Rates And Equilibrium

Measures how fast the reactants are being used up or products are being formed

The change in concentration of a reactant or product in a given time

The particles collide with the correct orientation The particles must have sufficient energy to overcome the activation energy barrier of the reaction

The minimum amount of kinetic energy required for a reaction to occur

Increasing temperature Increasing SA Increasing pressure Increasing concentration Use of a catalyst

Temperature increases the rate of reaction by… Increases KE of particles Greater proportion of the particles will have at least the activation energy - more effective collisions Causes them to move faster and collide more frequently increasing the chances of effective collisions

Increasing concentration/pressure increases the rate of reaction It increases the number of particles in the same volume Particles are closer together Collide more frequently More likely to be more effective collisions

Catalysts increase rate of reaction They lower the activation energy By providing an alternative reaction pathway A greater proportion of particles will have enough energy to react

How quickly the reactants are used up = removal of reactant How quickly the products are formed = formation of a product

• colour changes in solutions • mass change • volume of gas produced • pressure changes in gasses • changes in conductivity

1) add reactants to conical flask 2) record initial mass 3) add catalyst 4) record mass at regular intervals until no change

1) add reactants to conical flask and replace bung 2) record the initial volume 3) add catalyst 4) measure volume at regular interval changes

A catalyst increases the rate of reaction by providing an alternative reaction pathway with a lower activation energy. The catalyst is chemically unchanged by the end of the reaction

A reaction in which the catalyst has a different physical state from the reactants Reactants = gases Catalyst = solid

Reaction takes place on surface of the catalyst Reactant is absorbed onto surface (forms weak bonds) Product leaves through desorption

A reaction in which the catalyst and the reactants are in the same physical state Aqueous

Catalysts react with the reactants to form an intermediate species Which breaks down to give products and regenerates the catalyst

• Catalysts lower the production costs By producing more products in shorter time And reducing the energy required by using lower temperatures • change the properties of a product to make it more useful

-Preserves energy -Reduces waste By producing fewer pollutants as higher at economy Convert harmful pollutants into safer ones

The spread of molecular energies in gases

Shows the different kinetic energies a number of molecules have in a substance

Temperature increases the average energy of the molecules - molecules have higher energy The graph will stretch • the peak will be lower • and further along the x axis • area is the same

Activation energy is lower on graph More particles in effective collisions area

The equilibrium that exists in a closed system when the rate of the froward reaction is equal to the rate of the reverse reaction and concentration do not change