rate of reaction

• The presence of a catalyst can affect the rate of reaction, as catalysts can speed up the reaction without being consumed in the process.
• A rise in temperature increases the reaction rate by increasing the kinetic energy of molecules and thus their velocity of collisions.
• Average Rate = Total Change / Time Taken
• Enzymes are catalysts that lower the activation energy barrier and increase the reaction rate.
• The rate of reaction is the change in concentration with time.
• Concentration of reactants is another factor that affects the rate of reaction, as a higher concentration of reactants usually results in a faster reaction rate.
• The surface area of reactants is a factor that affects the rate of reaction, as a larger surface area allows for more collisions between particles and increases the reaction rate.
• Increasing temperature increases the kinetic energy of particles, causing them to collide more frequently and with greater force, increasing the likelihood of successful collisions leading to chemical reactions.
• Reactions between gases occur more quickly than those between solid/liquid reactants due to increased surface areas.
• what four things effect the rate of a reaction?

  Temperature, concentration of reactants, surface area, presence of a catalyst.
• what is the effect of increasing the temperature on rate of reaction ?

  it will increase the particles energy so more successful collisions
• what is the effect of increasing the concentration of a solution on rate of reaction ?

  as there are more particles the collisions are more frequent
• what is the effect of increasing the pressure of gasses on the rate of reaction ?

  less space between particles mean more frequent collisions
• what will increasing the surface area of solids do to the rate of reaction?


  it means more particles are exposed so more particles are able to react
• what is activation energy ?

  the minimum energy required to start a reaction
• what does a catalyst do to the activation energy ?

  it lowers the activation energy
• why does a catalyst lower the activation energy ?


  provides an alternative reaction pathway.
• what is the rate of reaction ?

  The speed at which a chemical reaction takes place.
• what is the unit for rate of reaction involving a change in mass ?


  grams per second (g/s)
• what is the unit for rate of reaction involving change in volume ?

  cm cubed/seconds. cm3/s
• why will lowering the pressure reduce the rate of reaction ?


  the molecules are further apart
• why will increasing the pressure increase the rate of reaction ?


  the molecules are closer together