Process

Task 1: Classifying Endothermic and Exothermic Reactions

You will visit the Chemical Paradigms wiki and read lesson 1 about Exothermic and Endothermic reactions. (You DO NOT have to read the experiment described in this lesson) After reading the information, you will complete exercise 1 question 1. Write the chemical reaction and classification in your lab journal. 
 

Task 2: Virtual Simulation Lab

                                   
 
Investigate the Fact Monster SimLab to identify:
Write all observations and temperature changes for each of the three reactions in your lab journal. Identify each of the three reactions as endothermic or exothermic. When the simulation is over, write the balanced chemical reaction for each of the three reactions you watched in the simulation. 

 

Task 3: In-Class Experiment

 
You will actually complete the three experiments you watched in the simulation experiment in class. For all three experiments, record all observations and initial and final temperature changes in lab journal. Also, classify each reaction as endothermic or exothermic. 
 
NH4Cl:
  1. Fill the beaker with 300ml of water.
  2. Place the thermometer in the beaker.
  3. Record the initial temperature in your lab journal.
  4. Dissolve 2 grams of NH4Cl in water.
  5. Observe the temperature change after five minutes.
  6. Record the final temperature in your lab journal. 
  7. Record whether the reaction was endothermic or exothermic.
CaCl2:
  1. Fill the beaker with 300ml of water.
  2. Place the thermometer in the beaker.
  3. Record the initial temperature in your lab journal.
  4. Dissolve 2 grams of CaCl2 in water.
  5. Observe the temperature change after five minutes.
  6. Record the final temperature in your lab journal. 
  7. Record whether the reaction was endothermic or exothermic.
NaCl:
  1. Fill the beaker with 300ml of water.
  2. Place the thermometer in the beaker.
  3. Record the initial temperature in your lab journal.
  4. Dissolve 2 grams of NaCl in water.
  5. Observe the temperature change after five minutes.
  6. Record the final temperature in your lab journal. 
  7. Record whether the reaction was endothermic or exothermic.

Task 4: Identify the "Unknown"

I will give each of you an "unknown" chemical. It will be one of the three chemicals- NH4Cl, CaCl2, or NaCl. You will repeat the experiment on the "unknown" chemical and identify if based on how its chemical bonds break to form other bonds in a reaction and how this causes a change in temperature. 
  1. Fill the beaker with 300ml of water.
  2. Place the thermometer in the beaker.
  3. Record the initial temperature in your lab journal.
  4. Dissolve the "unknown" in water.
  5. Observe the temperature change after five minutes.
  6. Record the final temperature in your lab journal. 
  7. Identify the "unknown" as NH4Cl, CaCl2, or NaCl based on the change in temperature, if any, and record in your lab journal.
  8. Record whether the reaction was endothermic or exothermic.
 

Task 5: Energy Level Diagrams

Revisit the Chemical Paradigms wiki and read the material over energy level diagrams. Based on the information from the wiki and what you have learned throughout the lesson, draw an energy level diagram for each of the chemical reactions in your lab journal. 

Task 6: YouTube Video

For the final task, you are to watch the Endothermic & Exothermic Reactions video on YouTube. When you have completed the video, you should answer the following question in your lab journal:

Based on what you learned and observed from the virtual simulation, in class experiment, and YouTube video, what happens to the molecules in and endothermic reaction and exothermic reaction? How does this produce a temperature change, if any?