Chemistry P2 C6 *

High temperature - particles have more energy which means particles move faster = quicker reaction

High concentration - higher number of particles to be able to take part in reaction

Increase pressure - if particles are closer together = will react quicker

Larger surface area - larger area for particles to react together, speeding up reaction

• Reactants only take place when particles collide with certain amount of energy
• Activation energy - minimum amount of energy needed for reaction
• Rate of reaction depends on:
  • Frequency of collisions in particles
  • Energy with which particles collide
• If particles collide with less energy than activation energy, they will not react (particles will bounce off each other)
• Temperature:
  • Higher termperature= faster the rate of reaction
    • Particles have more energy to move, likely to move faster+collide with other particles
    • When particles collide there is more energy:number of successful collisions increasse

Reversible reaction is in equilibrium when rate of forward reaction = rate of backwards reaction

Exothermic(give out heat) + Endothermic (take in heat)

• Reversible reaction:
  • if forward reaction is exothermic, backward reaction is endothermic
  • if forward reaction is endothermic, backward reaction is exothermic  

States if change is made to system in dynamic equilibirium, system will react to oppose change until equilibrium is reached

• Causes position to shift  which changes the relative amount of reactants/products to shift

Changes to reaction systems:

• Temperature
• Pressure
• Concentration

• Response of reaction system depends on properties of forward/backward reaction

Increase in temperature:

• equilibrium shifts to decrease temperature
• equilibrium shifts in endothermic direction(that takes in heat) 
  • increases the amount of product formed  by endothermic reaction
  • decrease the amount of product fromed by exothermic reaction

Decrease in temperature:

• equilibrium shifts to increase temperature
• equilibrium shifts in exothermic direction(that gives out heat)
  • increase amount of product formed by exothermic reaction
  • decrease amount of product formed by endothermic reaction

Increase in pressure

• equilibrium shifts to decrease preesure
• equilibirum shifts in direction of fewest molecules

Decrease in pressure

• equilibrium shifts to increase pressure
• equilibrium shifts in direction of most molecules

Increase in concentration of a substance

• equilibrium shifts to decrease amount of substance
• equilibrium shifts to right

Decrease in concentration of a substance

• equilibirum shifts to increase amount of substance
• equilibrium shifts to left

• Dynamic equilibrium will try to oppose any change placed on it
• If a reaction that is exothermic from left to right is heated, less product will be made
• If pressure is decreased, the equilibrium will shift so there are more molecules of gas
• if concentration of reactant is increased, equilibrium will shift to right causing concentration of product to increase