ISO-8859-1Seeing Specific Heat and Latent HeatSeeing Specific Heat and Latent Heat
Model and scripts by Arie Aziman and Carlos Cardena (modified from an original model by Dan Damelin)
Heating a Solid Object - the Process of Evaporation
Specific heat is the measure of the heat energy required to raise the temperature of a given quantity of a substance by one degree kelvin. Latent heat of melting describes the amount of heat required to melt a solid.
Run the following model, and watch for the periods of Specific Heat and Latent Heat.
We begin with a model of a solid substance. An example would be ice (solid H2O) but we could also consider one of the elements - in this case Sodium or Potassium. If heat is steadily added, the system will increase in Temperature until ? ?
Again, be alert to what is going on in the left hand window as the Temperature levels out in the graph !
When a solid is undergoing melting, the temperature basically remains constant until the entire solid is molten (liquid). During this process, heat is absorbed creating bonds, and this exactly corresponds to the heat being input. What does this mean about the Temperature?
Now answer all of the questions below:
Question #1 Question #2
The above simulation demonstrates the specific heat and the latent heat, but contains relatively few molecules (think of Avogadro's number ! ) so that the phase change is not smooth. Real phase changes are very steady processes and produce a nearly horizontal temperature line.
The next page will conclude with some detailed information regarding Phase Changes.
Next
16.06.0true1616.06.011true16.06.0true6.06.0truetrue6.06.0truetrue6.06.016.06.0true16.06.0org.concord.mw2d.activity.AtomContainer03EvaporationPC$0.mmlfalsefalseorg.concord.modeler.PageBarGraph0Kinetic Energy/ParticleKinetic energy55250true510true-100000.01.00.2621181607246399255 0 0org.concord.modeler.PageBarGraph0Potential Energy/ParticlePotential energy55250true510true-ffff01-1.00.0-0.0652289167046547org.concord.modeler.PageXYGraph0Total Energy/ParticleKinetic Energy/Particlefalse-0.80.3false0.04000.0200250Total energy (eV)Temperature (K)272157-1-1falsefalseLine6.06.01org.concord.modeler.PageButtonStart adding heatStart adding heat to the systemRaised Bevelfalseorg.concord.mw2d.models.MolecularModel0trueExecute MW script11truetrueorg.concord.modeler.PageMultipleChoicetrue4400200<html>
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At what temperature does the Phase Change occur ?
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trueabout 300 Kabout 800 Kabout 1500KAbout 2000 K2-111112org.concord.modeler.PageTextArea400200<html>
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What is happening to the molecules of the substance during the phase
change ? What is happening to the bonds?
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The molecules are breaking away from the substance. Bonds are being broken which allows the disassociation of the molecules.-1110.010.010.01404Conclusion.cml10.010.0