Worksheet: Understanding Chemical Reaction Rates

Part A: Basic Concepts of Reaction Rate

1. In your own words, explain what a "reaction rate" means in chemistry.
   
   
   

2. Complete the following sentence: A fast reaction rate means _______________________________, while a slow reaction rate means ________________________________.

3. Circle the correct answer: If a chemical reaction has a high rate, it means:

   a) The reaction produces a lot of products b) The reaction happens quickly c) The reaction requires high temperature d) The reaction needs a catalyst

Part B: Factors Affecting Reaction Rates

4. List at least four factors that can affect the rate of a chemical reaction.
   
   
   
   

5. Match each factor with its effect on reaction rate:

   a) Increasing temperature _____ Provides an alternate pathway for the reaction

   b) Adding a catalyst _____ More particles available to collide

   c) Increasing concentration _____ Particles move faster and with more energy

   d) Increasing surface area _____ More area for particles to collide

6. Draw a simple diagram showing how breaking a tablet into smaller pieces would affect reaction rate. Label your diagram.
   
   
   
   
   
   
   
   
   

Part C: Particle Behavior in Chemical Reactions

7. For a chemical reaction to occur, what must happen between particles?
   
   
   
   
   

8. Explain in 2-3 sentences what the "collision theory" tells us about chemical reactions.
   
   
   
   
   

9. Complete the diagram below by drawing how particles behave:

   a) Before a reaction

   b) During a collision

   c) After a successful reaction has occurred
   
   
   
   
   
   
   
   

Part D: Exploring Variables that Affect Reaction Rates

10. Experiment scenario: A student drops an antacid tablet in water and measures how long it takes to dissolve completely.

    a) Predict how changing the water temperature from cold to hot would affect the dissolution time. Explain your reasoning.
    
    
    
    b) Predict how crushing the tablet would affect the dissolution time. Explain your reasoning.
    
    
    
    

11. Consider a reaction between zinc metal and hydrochloric acid.

    a) How would doubling the concentration of the acid affect the reaction rate?
    
    b) Explain WHY this change in concentration affects the reaction rate in terms of particle collisions.
    
    

12. For each scenario, indicate whether the reaction rate would increase (I), decrease (D), or remain unchanged (U):

    a) ____ Adding more reactants to the mixture

    b) ____ Lowering the temperature of the reaction

    c) ____ Adding a catalyst to the reaction

    d) ____ Cutting a solid reactant into smaller pieces

Extension Activity

13. Design a simple experiment to test how temperature affects reaction rate. Include:
    • Materials needed
    • Steps to follow
    • How you would measure the reaction rate
    • What results you would expect and why