Determining Buffering Determining Buffering CapacityCapacity

Bio Sciences: pH

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BellworkBellwork

How would you convert 327ml to L? What is the volume in L?

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ObjectivesObjectives

1. Explain the plot of pH vs. volume to show buffering capacity of a solution.

2. Graphically represent the difference between a buffered and un-buffered solution.

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TerminologyTerminology

Henderson–Hasselbalch: Used to prepare buffer solutions and to estimate charges on ionizable species in solution, such as amino acid side chains in proteins

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Determining Buffer Capacity Lab, Introduction and

BackgroundWe will be comparing pH changes of a buffered vs. un-buffered solution. Normally buffering capacity is calculated using the Henderson–Hasselbalch equation: “Used to prepare buffer solutions and to estimate charges on ionizable species in solution, such as amino acid side chains in proteins”

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Determining Buffer Capacity Lab, Objectives

I. Explain the plot of pH vs. volume to show buffering capacity of a solution.

II. Graphically represent the difference between a buffered and un-buffered solution.

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Determining Buffer Capacity Lab, Tips

Read all procedure and double check with partner.Carefully count drops dispensed from NaOH.Volume NaOH is additive, so amount should increase in table with each dropIf unsure ASK!

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ClosureClosure

Find another group and compare your buffered and un-buffered graphs to their. Do you have similar shaped graph, if no how do they differ.?

Are your buffering capacities with in 10% of each other? If no, purpose one (1) reason why.

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