Rates of reactions

• Activation energy


  The minimum energy needed to start a reaction
• Rate of reaction


  How quickly a chemical reaction happens
• Rate of reaction


  • Measures how many reactants are used up and how much product is formed in a certain time
• Particle theory


  During a chemical reaction the particles in the reactants are moving and colliding
• Reactants


  The substances that combine to form a new substance (product)
• Activation energy


  The minimum energy needed for the colliding particles to have in order for a new product to form
• Activation energy


  1. Particles must collide with enough energy to break the bonds in the molecules

  2. Once the bonds are broken the atoms can rearrange to make the products
• Reactions ordered from fastest to slowest


  • Dynamite exploding
  • Baking a cake
  • Antacid tablet relieving heartburn
  • Milk going sour
  • Wine fermenting
  • Iron nail rusting
  • Limestone rock weathering
• Reaction C


  • Slowest rate of reaction
• Reaction B


  • Fastest rate of reaction
• Reactions A and D


  • Likely had the same testing conditions
• As temperature increases


  The speed of the reaction increases
• As concentration increases


  The rate of reaction speeds up
• Surface area


  A measure of the amount of a substance that is exposed
• Smaller particle size


  Greater rate of reaction
• Catalyst


  A substance that speeds up the rate of a chemical reaction without being consumed or changed
• Adding a catalyst


  Lowers the activation energy, making it easier for particles to react, increasing the rate of reaction
• Biochemical reaction


  A reaction that takes place inside a living cell, where a new product is formed
• Biochemical reactions


  • Digestion
  • Respiration
  • Photosynthesis
• Key terms


  • Activation energy
  • Rate of reaction
  • Temperature
  • Concentration
  • Surface area
  • Catalyst
  • Biochemical reaction