Distillation and the Role of Weak Forces

Interactive model, with minimal support

Overview and Learning Objectives

Substances in solution have different van der Waals attractions for each other and they can be separated and retrieved independently by the process of distillation that uses this principle of differential "stickiness." In this activity students manipulate temperature and "stickiness" in order to model effective distillation, which is an important technique for water purification and many industrial processes.

Students will be able to:

• compare the separation of different substances in mixtures and explain why some are easier to separate than others;
• experiment with model variables such as strength of van der Waals attractions, temperature, and composition of mixtures to see the impact on distillate.

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Assessment

Performance assessment in MW:

http://www.concord.org/~barbara/workbench_web/models/jnlps/Distillationassess1.jnlp

PDF file for print assessment:

http://www.concord.org/~barbara/workbench_web/pdf/Distillation_Assess10.pdf

PDF file assessment RUBRIC

http://www.concord.org/~barbara/workbench_web/pdf/distillation_rubric_8_07.pdf

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Central Concepts

Key Concept:

Substances in solution can be separated and retrieved independently by the process of distillation.

Additional Related Concepts

Physics/Chemistry

• Solutions
• Van der Waals

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Benchmarks and Standards

AAAS

• THE PHYSICAL SETTING: ENERGY TRANSFORMATIONS - Different energy levels are associated with different configurations of atoms and molecules (Full Text of Standard)
  
  
• THE PHYSICAL SETTING: ENERGY TRANSFORMATIONS - Transformations of energy usually produce some energy in the form of heat, which spreads around by radiation or conduction into cooler places (Full Text of Standard)
  
  

NSES

• Physical-Science: Matter Structure/Properties - 4 The physical properties of compounds reflect the nature of the interactions (Full Text of Standard)
  
  

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Extensions and Connections

Mass is not a factor in distillation, but if students want to be convinced that it is not, they can go to the activity Atomic Mass and Boiling Point (http://molo.concord.org/database/activities/275.html).

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Activity Credits

Created by CC: Molecular Literacy using Molecular Workbench

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Requirements

• Java 1.5+ - Java 1.5+ is available for Windows, Linux, and Mac OS X 10.4 and greater. If you are using Mac OS X 10.3, you can download MW Version 1.3 and explore within it instead.

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