Rate of reaction

• Rate of reaction is how fast the reactants are changed into products
• one of the slowest reactions is the rusting of iron. Other examples include chemical weathering
• A moderate speed reaction would be the metal magnesium reacting with an acid to produce a gentle stream of bubbles
• Burning is a fast reaction, but explosions are even faster and produce a lot of gas
• • you find the speed of a reaction by measuring the amount of product formed
  • The steeper the line on a graph, the faster the rate of reaction
  • over time the line becomes less steep as the reactants are used up
  • The quickest reactions have the Steepest lines and become Hat in the least time
• particles must collide with enough energy in order to react

  Rate of a chemical reaction depends on:

  • the collision frequency of reacting particles (how often they collide). The more collisions, the faster the reaction
  • The energy transferred during a collision. Particles have to collide with enough Energy for the reaction to be succesful

  the minimum amount of energy particles need to react is called the activation energy

  Facton that increase either of these increase rate of reaction
• Rate of reaction depends on:

  1. temperature
  2. the concentration of a solution or the pressure of gas
  3. Surface area - this changes depending on the size of the reactants
  4. the presence of a catalyst
• Because more collisions cause the rate of reaction to increase:

  1. temp causes the particles to move faster which makes the reaction rate increase, because there are more collisions and the collisions Will have more energy
  2. Increasing concentration or pressure increases the rate because more particles means more collisions
• If the surface area is larger, the particles around it will have more area to work on, making collisions more frequent
• Catalysts work by decreasing the activation evergy needed for a reaction to occur by providing an alternative reaction pathway with a lower activation energy