Titration Technique Lecture Notes

Introduction

• Lecturer: Jared Hyman, Assistant Professor of Chemistry at Elon University
• Topic: Proper titration technique
• Series: First of a two-part series on titration
• Purpose: Quantitatively determine the concentration of an unknown solution (analyte) by adding a known concentration solution (titrant)
• Endpoint: Marked by adding an indicator to the analyte

Equipment Needed for Titration

• Carolina's Complete Burette Assembly
  • Burette: Long, narrow graduated tube with a stopcock
    • Markings: Lowest at the top, highest at the bottom
  • Ring Stand and Burette Clamp: Used to mount and secure the burette
• Other Materials
  • Small funnel for filling the burette
  • 125 mL Erlenmeyer flask
    • Advantageous shape for vigorous swirling
  • Volumetric pipette and pipette bulb
  • Wash bottle with deionized water
  • Beaker or flask of titrant and analyte
  • Selected indicators for the reaction
  • Reading card for meniscus reading
  • White paper to help visualize the endpoint

Preparing the Burette

• Rinse thoroughly with deionized water, then with titrant
• Ensure titrant flows into the flask and not clinging to the burette walls
• Mount burette vertically in the clamp
• Fill burette with titrant using a funnel; check for air bubbles
• Remove funnel and release a few milliliters of titrant to remove trapped air
• Record starting volume
  • Read from bottom of the meniscus at eye level
  • Record to the nearest hundredth of a milliliter

Performing the Titration

• Transfer Analyte
  • Use volumetric pipette to transfer analyte to flask
  • Add indicator and swirl
• Record Initial Volume
  • White paper under flask helps detect color change
• Operating the Burette
  • Use two hands: one for stopcock, one for swirling
  • First titration is an estimate
  • Allow titrant to flow quickly, swirl continuously
  • When analyte becomes colored, close stopcock
  • Record final volume
• Endpoint Determination
  • Subtract initial from final volume for estimated titrant volume
  • Subtract 5 mL for safer addition before endpoint
  • Slow down addition when color begins to persist
  • Continue drop-wise addition until a faint color persists
  • Perform titrations in triplicate for accuracy
• Calculate Average Volume

Conclusion

• The process covered the steps to perform a titration accurately
• Next video: Determining concentration of an unknown acid solution
• For supplies, visit Carolina Chemistry's website

This summary captures the key points and procedures for conducting a titration as outlined by Jared Hyman in the lecture.