A Comparison of Liquid and Gas States

Interactive model, with minimal support

Overview and Learning Objectives

In this activity, students will run molecular simulations of a substance in gas and liquid phases side by side long enough for a recorder to gather data. They will then open a graph of the pair correlation function (PCF) for each state of matter and observe how the attractive forces affecting a molecule in liquid phase result in it attracting other molecules in close proximity to itself, and at specific distances. Students will observe that the gas phase molecule, on the other hand, has only a slight ability to attract other molecules close to it.

Students will be able to:

• understand the difference in the arrangement and forces between molecules in dynamic gas and liquid states;
• explain a graph that correlates the structural preference of molecules with their state of matter;
• understand that mathematical functions can represent aspects of physical situations.

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Central Concepts

Key Concept:

In a gas phase, there is space between atoms, and these atoms move randomly and chaotically in space. Atoms in liquids are generally fairly close to one another. Viewed from the perspective of an atom, its neighboring atoms are able to move past one another to another position. The space left behind is then occupied by a different atom.

Additional Related Concepts

Physics/Chemistry

• Gas
• Liquid
• States of Matter

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Textbook References

• Biology (Miller and Levine) Prentice Hall 5th Edition - Unit I: Chapter 3 - Introduction to Chemistry
• BSCS Blue (8th Edition) - Chapter 3: Exchanging Materials with the Environment

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Benchmarks and Standards

NSES

• Physical-Science: Matter Structure/Properties - 5 Solids, liquids, and gases differ in the distances and angles between molecules (Full Text of Standard)
  
  

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Activity Credits

Created by CC Project: Molecular Workbench 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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