c6 - rate of reaction

• when water is added to cobalt chloride paper it turns from blue to pink
• the reaction will be endothermic in one direction and exothermic in the other
• equal amounts of energy transferred each way
• reversible reactions will reach equilibrium
• closed system - none of the reactants or products can escape
• equilibrium - forwards and backwards reaction are occurring at the same rate
• equilibrium depends on temperature, pressure and concentration
• le Chatelier's principle-If you change the conditions of a reversible reaction, the system will try to counteract the change

  
• decreasing the temperature will shift equilibrium in the exothermic direction
• increasing the pressure will move equilibrium in the direction where there are fewer molecules of gas
• change in concentration - equilibrium will shift to the right
• increasing the concentration of the reactants will increase the rate of the forwards reaction
• Increasing the concentration, increases the number of particles in the same volume
• Increasing the pressure, means the same number of particles are now in a smaller space
• Increasing the temperature increases the speed of the particles and increases the energy of each collision
• state five factors that affect the rate of a chemical reaction:

  • concentration of reactants
  • pressure of gases (volume)
  • surface area
  • temperature
  • catalysts
• a catalyst affects the rate of the reaction but is not used up - increases the rate of a reaction by providing a pathway for the reaction that has a lower activation energy
• when is dynamic equilibrium reached?

  • in a closed system when the forward & reverse reactions occur at the same rate & the concentrations of reactants & products remain constant
• describe Le Chatelier's Principle

  • if a system is at equilibrium & a change is made to any of the conditions, then the system responds to counteract that change & restore the equilibrium
• decrease temperature : equilibrium moves in exothermic direction
• increase temperature : move in endothermic direction
• increase pressure : equilibrium moves to the side with least number of molecules
• wherever concentration is increased, equilibrium shifts to the opposite side
• In a reversible reaction, if the forward reaction is exothermic, what would be the effect of decreasing the temperature?

  • Yield of products would increase