Chemical Thermodynamics : Entropy and Enthalpy

By observing a phase change reaction, students study entropy and enthalpy and discover their effects on reaction spontaneity.

Lab Summary:

Explore the concepts of entropy and enthalpy by measuring the change in temperature of a substance as it slowly cools and undergoes a phase change from liquid to solid. Investigate what factor determines whether a reaction is spontaneous or not when the enthalpy and entropy disagree.

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(student version)

Method:

Explore the concepts of entropy and enthalpy by measuring the change in temperature of a substance as it slowly cools from liquid to solid phase. Determine which factor dominates during the phase change.

Here's What You Need:

Probeware

• PASPORT Stainless Steel Temperature Probe (PS-2153)
• Xplorer GLX Graphing Datalogger (PS-2002)

Other Materials

• Small Tripod Base & Rod (SE-9451)
• Buret Clamp (SE-9446)
• Balance (SE-8756A)
• Hot plate
• Beaker, 250 mL
• Test tube, large
• Unknown Substance (Napthalene)
• Water

Lab Manual:

This activity is included in Chemistry with the Xplorer GLX (PS-2819A), complete with Teacher Information pages, student instructions and handouts, and sample data for a total of 19 probeware-based labs. For your convenience, we offer bundles which provide the probeware necessary for the activities in the manual. For more information on these resources and bundles, click here.