Effect of Concentration on Rate

• What happens to the rate of chemical reactions over time?

  Reactions are rapid initially, then slow down
• What is the key idea in chemistry that explains the shape of the reaction rate curve?

  Collision Theory
• According to collision theory, when can chemical reactions take place?

  When reacting particles collide with sufficient energy
• How is the rate of a chemical reaction determined?

  By the frequency of successful collisions
• What does the term 'frequency' refer to in the context of chemical reactions?

  The number of successful collisions per second
• Why do reactions slow down over time?

  Because the number of reactant molecules is running out
• What happens when all reactant molecules have run out?

  The reaction stops and collisions per second are zero
• If one container has twice the number of particles as another, what can be said about their reaction rates?

  The reaction rate is twice as fast in the first
• What is the effect of increasing the concentration of reactants on the quantity of product formed?

  More product is formed at the end
• How does the graph of a reaction with higher concentration differ from one with lower concentration?

  The line is steeper for higher concentration