NSCI 101/103

Lab 5: Chemical Processes

· On your own and without assistance, complete thisLab 5Answer Form electronically and submit it via theAssignments Folder by the date listed on yourCourse Schedule (underSyllabus).

· To conduct your laboratory exercises, use the Laboratory Manual that is available in the WebTycho classroom (Reserved Reading or provided by your instructor) or at the eScience Labs Student Portal. Laboratory exercises on your CD may not be updated.

· Save yourLab 5Answer Form in the following format: LastName_Lab5 (e.g., Smith_Lab5).

· You should submit your document in a Word (.doc or .docx) or Rich Text Format (.rtf) for best compatibility.

1. Define enthalpy.

2. What is the relationship between the enthalpy of a reaction and its classification as endothermic or exothermic?

3. With instant hot compresses, calcium chloride dissolves in water and the temperature of the mixture increases. Is this an endothermic or exothermic process?

Table 2: Hand Warmer Data

Table 1: Cold Pack Data

Experiment 1: Cold Packs vs. Hand Warmers

Time (sec)	Temp. (°C)
Initial
30
60
90
120
150
180
210
240
270
*300
330
360
390
420
450
Minimum Temp (°C):

Time (sec)	Temp. (°C)
Initial
30
60
90
120
150
180
210
240
270
*300
330
360
390
420
450
Minimum Temp (°C):

Graph your data from the tables. You may create the graph on any program, but make sure it can be integrated into this document.

1. Calculate the overall temperature change for the cold and hot pack substance.HINT: This is the difference in the maximum temperature and minimum temperature of each.

Cold pack?T:

Hand warmer?T:

2. Which pack works by an exothermic process? Use experimental data to support your answer.

3. Which pack works by an endothermic process? Use experimental data to support your answer.

4. Which pack had the greatest change in enthalpy? How do you know?