Learning Objectives:

• Understand the meanings of the words, exothermic and endothermic.
•  Identify endothermic and exothermic reactions experimentally.
• Learn to measure and quantify energy changes associated with physical and chemical changes.

Chemical reactions involve substances reacting to form new substances.  These chemical reactions can either produce heat or absorb heat.  If a chemical reaction produces heat, the reaction is considered exothermic; however, if energy is absorbed, the reaction is considered endothermic.  We can observe this energy transfer in the form of temperature change.  

In this lab, we will study how energy transfers occur in chemical processes.  By carefully measuring changes in temperature, we will be able to determine whether various chemical reactions are endothermic or exothermic in nature.  To study these changes, we will be constructing a simple calorimeter; a device that allows us to measure transfer of energy in the form of heat.      

• Read the lab before coming to class.  The expectation at Chamberlain (CCN/CU) is that you come to class fully prepared for lab.
• Always dress properly for lab.  Be sure to wear closed toed shoes and long pants to lab.  In lab, wear your safety equipment including goggles, lab coat, and gloves.
• Be careful when handling chemicals.
• Always check with your instructor regarding proper waste disposal.
• Listen carefully to the professor’s instructions and work safely.
• Always follow the rules outlined in the safety contract.
• If in doubt of how to use a piece of lab equipment, as you instructor.  Improper use of lab equipment can be dangerous or could damage lab materials.
• If you have any safety concerns, see your instructor.
• Use deionized water (DI water) in your experiments

Exploration 1: Understanding Energy Transfer Terminology

Complete the table below by defining each term and giving a real world example of this term

• Building a Calorimeter
• Materials: Styrofoam cup and lid, Thermometer, stir bar and stir plate
• Method:

Exploration 2: Heat of Solution for Sodium hydroxide (NaOH)

In this exploration, we will see how physical changes in atoms involve change in energy.  

• Materials: calorimeter, pellets of NaOH, DI water, thermometer, stir bar and stir plate
• Method:
• Results:

Exploration 3: Physical Change- Heat of Solution for potassium chloride (KCl)

• Materials: calorimeter, potassium chloride, DI water, thermometer, stir bar and stir plate
• Method:
• Results:

Exploration 4: Chemical Change - Reaction between an Acid and Base

• Materials: Styrofoam cup and lid to build a calorimeter, 1 M NaOH, 1 M HCl, thermometer, stir bar and stir plate
• Method:
• Results:

Exploration 5: Chemical Change - Reaction between stomach acid and antacid

• Materials: Styrofoam cup and lid to build a calorimeter, two antacid tablets, mortar and pestle, 0.36 M HCl, thermometer, stir bar and stir plate
• Method:
• Result:
• Conclusions
• Questions:

1. Which of the reactions were exothermic in nature and which were endothermic?
2. From the previous experiments, if you heated the water, would this alter their exothermic or endothermic behavior?
3. What was the reason that you needed to wait for the temperature to stabilize?
4. A chemical reaction requires more energy to break bonds than the energy released from the formation of new bonds.  What would I classify this reaction as?
5. When you leave a cold bottle of soda out on a warm humid day, water begins to condense on the surface of the bottle.  Describe what is happening in terms of energy change.