Activity Number
280
Editable
Overview and Learning Objectives
Assessment
Central Concepts
Textbook References
Activity Credits

Molecular Crystals (7-page activity)

Interactive, scaffolded model

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Overview and Learning Objectives

Students are introduced to a particular type of crystal, a molecular crystal held together with weak forces.

Students will be able to:

  • compare properties of polymorph crystals as they relate to changes in temperature and pressure;
  • examine and interpret x-ray diffraction results of the crystals;
  • determine the implication of crystal variations in technology.

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Assessment

Adapted from test by Dave Wilson, Parkland College

http://www.concord.org/~barbara/workbench_web/models/pdf/MolecularXlsAssess.pdf

Rubric

http://www.concord.org/~barbara/workbench_web/pdf/molecularX_rubric_8.07bt.pdf

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Central Concepts

Key Concept:

There are four types of crystals, primarily characterized by the interatomic interactions that hold the unit cells together. Molecular crystals have unit cells held together by hydrogen bonds. As a result, molecular crystals are typically softer and have lower melting points than the other types of crystals.

Additional Related Concepts

Physics/Chemistry

  • Crystal
  • Crystallization

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Textbook References

  • Cell Biology (Pollard and Earnshaw) Saunders 2002 - Chapter Two: Molecular Structures

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Activity Credits

Created by CC Project: Molecular Workbench using Molecular Workbench

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NSF Logo
These materials are based upon work supported
by the National Science Foundation under grant numbers
9980620, ESI-0242701, EIA-0219345, DUE-0402553, and 0628181.

Any opinions, findings, and conclusions or recommendations expressed in this
material are those of the author(s) and do not necessarily reflect
the views of the National Science Foundation.