1. Module 1

1.21. Page 3

Module 1: Lesson 4

Module 1—Thinking Energy

Reflect and Connect
 
Energy Change of a Hot Pack

 

In this lesson you learned about enthalpy change and how an enthalpy change might be quantified using calorimetry. Complete the following activity to test your understanding of what you have learned.
 

Watch the video “Operation of a Hot Pack.”

 

The following data were collected from a calorimetry experiment investigating the energy released by the hot pack shown in the video. Use your observations from watching the video and the data provided to complete the Analysis section below.

 

Data

 

mass of water in calorimeter = 550 g
initial temperature of water = 22.3ºC
highest temperature of water = 30.7ºC

 

Analysis

 

RC 1. The contents of the hot pack are listed as sodium acetate, water, and a metal disk. State the change that occurs to the arrangement of the sodium acetate particles during the operation of the hot pack.

RC 2. Is the type of change identified in your answer to RC 1 an example of a change in kinetic energy or potential energy? Support your answer.

RC 3. Explain why the change identified in your answer to RC 2 represents an enthalpy change.

RC 4. Use the data provided to determine the enthalpy change of the hot pack.

RC 5. Is the enthalpy change of the hot pack an exothermic or endothermic process?  Support your answer by making specific reference to the data provided.

 

Save a copy of your responses in your course folder and submit a copy to your teacher.

 

Reflect on the Big Picture
 
Recharging Hot Packs

 

A photograph shows a pot containing boiling water. A cloth containing a hot pack is in the water.


 

The hot pack used in the previous activity is reusable. When the hot pack is placed in boiling water, the solid sodium acetate dissolves and forms a colourless solution within the bag. If your ecotour takes place in winter, hot packs may be an essential piece of equipment for your operation. That could mean a lot of hot packs.

 

RBP 1. How might a reusable hot pack containing sodium acetate help minimize the negative ecological impact of your ecotour operation? Consider aspects such as energy changes and the reactivity and toxicity of the substances associated with the hot pack in developing your answer. Place a copy of your response in your ecotour planning sub-folder.

 

This is the third of six assignments that you can submit as part of your Module 1 Assessment. For more information, refer to the Module 1 Assessment.

 

Module 1: Lesson 4 Assignment

 

There is no assignment for this lesson.