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In this video, Legos® are used to create possible molecular level models of a buffer. This is done to better understand how a buffer works and the components a buffer must contain in order to be effective. Students evaluate these models against a set of criteria determined at the beginning of the video and then consider other parameters that must be taken into account when designing a buffer.

Learning Objectives

After watching this video students will be able to:

  • Describe how the structure, or composition, of a buffer functions to resist changes in pH.
  • Explain how the choices made in buffer design impact the properties of a buffer.

Funding provided by the Singapore University of Technology and Design (SUTD)

Developed by the Teaching and Learning Laboratory (TLL) at MIT for SUTD

MIT © 2012

Related Resources

Instructor Guide

Buffers Instructor Guide (PDF)

It is highly recommended that the video is paused when prompted so that students are able to attempt the activities on their own and then check their solutions against the video.

During the video, students will:

  • Explain why a solution comprised solely of an acid in water could not effectively resist changes to its pH when more acid is added.
  • Explain why a solution of a strong acid and a strong base will not resist changes in pH.
  • Write the equilibrium expression for a weak acid.
  • Evaluate the ability of a solution of a weak acid and strong base to create an effective buffer.
  • Brainstorm factors that should be considered when designing a buffer solution.
  • Consider how the ratio of weak acid to conjugate base will affect the buffering capacity of a solution.

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