rates of reaction

• the steeper the slope the faster the reaction
• what does it mean if on a graph there is a steep slope

  fast reaction
• mean rate of reaction = quantity of product formed / time taken
• mean rate of reaction = amount of reactant used / time taken
• what does the graphs slope tell us

  rate of reaction
• to calculate the specific rate of reaction using a tangent do - change in y / change in x
• what does collision theory state

  chemical reactions can only take place when reacting particles collide with each other. The collisions must have sufficient energy
• chemical reactions can only take place when particles collide with eachother
• the rate of chemical reaction is determined by

  the frequency of successful collisions
• the rate of chemical reaction is determined by the rate of successful collisions
• the rate of reaction is proportional to the concentration
• particles in a solution can only react with particles on the surface of a solid
• rate of reaction increases when we increase the surface area
• what happens to the rate of reaction when we increase the surface area

  the rate of reactions increases because we have more collisions per second
• what is the activation energy

  the minimum amount of energy that the particles must have in order to react
• increasing the temperature increases the rate of reaction
• why does increasing the temp increase rate of reactions

  it increases the particles energy , it increases the frequency of collision since they move faster , the collisions have more energy so more can overcome the activation energy barrier
• temperature and reaction rates are proportional
• what increases the rate of reaction

  high surface area , high temperature
• what are catalysts

  something that increases the rate of reaction but isnt used up
• what are the benefits of catalysts

  they allow us to carry out reactions without temperature increase which saves money

  we can use them again and again
• the rate of reactions depends on the number of particles that have enough energy to cross the activation energy barrier and collide successfully
• how do catalysts increase rate of reaction

  by providing a different pathway for the reaction that has a lower activation energy
• catalysts provide a pathway with a lower activation energy
• we dont include catalysts in the chemical equation for a reaction
• why dont we include catalysts in chemical reactions

  they are not used up in a reaction so they are not a reactant
• different reactions need different catalysts
• we can change the direction of reversible reactions by changing the conditions
• if a reversable reaction is exothermic in one direction then its endothermic in the opposite
• what is the point where forward and reverse reactions take place called

  equilibrium
• if a system is at equilibrium and the conditions change them the system responds to counteract the change
• if we increase the temperature of a system then the equilibrium will shift to reduce the temp
• if temp in a system decreases then it would cause an exothermic reaction which increases the temp
• pressure involves reactions with gases
• the pressure of a gas depends on the number of molecules
• if we increase the pressure of a reversable reaction what happens

  the position of the equilibrium shifts to the side with the smallest number of molecules
• what factors increase the rate of reaction

  temp , surface area , concentration , pressure