Activity Number
54
Not Editable
Overview and Learning Objectives
Assessment
Classroom Practice
Central Concepts
Textbook References
Benchmarks and Standards
Extensions and Connections
Activity Credits
Requirements

Exploring Ionic Compounds (Salt) (a 5 pp activity)

Interactive, scaffolded model

Activity Screenshot

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This Activity Requires:

  • 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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Overview and Learning Objectives

In this model-based activity, students will learn the main concepts behind the process of dissolving. They begin by discovering the properties of ionic and polar compounds and observe that in order to be water-soluble, molecules should carry an electrical charge.

Working with models, students compare the solubility between ionic compounds such as table salt, polar organic molecules such as glucose, and non-polar organic molecules such as oil. They observe how water molecules attract ionic or polar substances, leading to the dissolving of various materials, and how non-polar molecules are pushed out by water, "preferring" to stick to each other.

Students will be able to:

  • describe how the presence or absence of electrical charge (positive, negative, polar, or neutral) affects whether a substance will be dissolved by water;
  • explain that on the microscopic level dissolving includes three simultaneously occurring dynamic processes: interactions between water molecules, interactions between particles of the substance, and interactions between those particles and water;
  • reason that for dissolving to occur, the interactions between molecules of the substances with water molecules must be stronger than their attraction to each other.

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Assessment

1a. What happens to salt on an atomic level (include molecules and ions in your description) when it dissolves in water? Describe the way in which the salt and the water interact.

1b. Alcohol is slightly polar. What happens to salt on an atomic level when it is placed in alcohol?

1c. Draw a picture that shows a salt solution in water. Be sure to label your picture or provide a key for any symbol you use.

1d. Draw a picture that shows a salt solution in alcohol. Be sure to label your picture or provide a key for any symbol you use.

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Classroom Practice

http://www.concord.org/~barbara/workbench_web/unitIII_mini/act_sol_solutions.html

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Central Concepts

Key Concept:

Water is a great solvent, but all substances that water can dissolve must be either polar or ionic (either positively or negatively charged). The polar water molecules attract charged particles and push out non-charged particles. Water is attracted to itself, to other polar molecules, ionic substances, and to non-polar substances.

Additional Related Concepts

Molecular Biology

  • Polar molecules
  • Polar nature of water

Physics/Chemistry

  • Charge
  • Concentration
  • Dissolving
  • Ionic bonds
  • Molecule
  • Salt
  • Solubility
  • Solutions

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Textbook References

  • Biology (Miller and Levine) Prentice Hall 5th Edition - Unit 1: Chapter 4 - The Chemical Basis of Life
  • Biology: Concepts and Connections (Pearson) 5th Ed. - Chapter 3: The Molecules of Cells
  • Biology: Concepts and Connections (Pearson) 5th Edition - Chapter 2: The Chemical Basis of Life
  • Biology: Exploring Life - Chapter 4: The Chemical Basis of Life
  • Biology: Exploring Life - Chapter 5: The Molecules of Life
  • Biology: The Dynamics of Life - Chapter 6: The Chemistry of Life
  • BSCS Blue (8th Edition) - Chapter 1: The Chemistry of Life
  • Web of Life - Chapter 2: Chemical Basis of Life

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Benchmarks and Standards

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

http://www.concord.org/~barbara/workbench_web/unitIII_mini/ext_solutions.html

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Activity Credits

Created by CC Project: Molecular Workbench using Molecular Workbench + Pedagogica

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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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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.