Collision theory and equilibrium Flashcards
How do you measure rate of reaction
Difference in volume of reactants, Formation of products
Collision theory
Particles must collide with correct orientation and with a sufficient amount of energy to overcome the activation
5 ways to change the rate of reaction
Temperature, surface area, concentration/pressure/volume, catalyst and nature of reactants
How does changing temperature change the reaction rate
As temperature increases, average kinetic energy increases, More particles have a sufficient amount of energy to overcome the activation energy, Increases frequency of collisions, Increases % of collisions
How does changing surface area change the reaction rate
Particles have a larger area to react over, increasing reaction rate, Increases frequency of collisions, Same % of collisions
How does changing the concentration/pressure/volume change the reaction rate
Increased number of particles per unit (particles closer together), Increase frequency of collisions, Same % of collisions
How does adding a catalyst change the reaction rate
Provides an alternative pathway with a lower activation energy, Not used up in the reaction, Increased frequency of collisions, Increased % of collisions?
How does the nature or reactants change the reaction rate
Lots of bond breaking = higher activation energy, Less bond breaking = lower activation energy = faster reaction rate, Exchanging a less reactive substance with a more reactive one will increase reaction rate
Requirements to achieve equilibrium
Closed system (closed container)- matter cannot be exchanged but energy can, Constant temperature
Characteristics of the equilibrium
Rate of forward reaction = rate of reverse reaction at constant temperature, Constant macroscopic properties- things we can measure/see (pressure, volume, colour)
Characteristics of the equilibrium constant
Mathematical relationship between the concentration of products and reactant at equilibrium, Temperature dependent meaning it is different for each reaction, Solids and liquids aren’t included as their concentration is constant, Doesn’t provide information about the rates of reaction, Gives indication of the relative proportions of the products and reactants
Equilibrium constant
doesn’t include solids or liquids, If greater than 1, products are favoured, If less than 1, reactants are favoured
Physical equilibrium
Products dissolve, no new products
Chemical equilibrium
New products are formed
Reversible reactions
Reactions that are more likely to have reversable reactions tend to have similar activation energies in the forward and reverse
