User:Matt Hartings/Notebook/AU Biomaterials Design Lab/2011/08/31

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Objective

Making buffers for class

Description

1. Add experimental record here. Include what, how, and why...

Data

Buffers

Stock solutions: 1.8M Acetic Acid

Media: Sodium Acetate Tris-Aquo

Media: Tris Base

Moles of each calculated using the buffer calculator for buffers made and used at 25C

• Buffer 1

Water

• Buffer 2

100 mL of 50mM Acetate Buffer pH 3.76

Calculations

Amount of acid component

M=nV

(1.8M)=(0.0045mol)(V)

V=2.5mL

Amount base component

m=MM*n

m=136.08g/mol*0.00048mol

m=0.0544g

• Actual measurement = 0.0563g
• Actual pH=3.6
• Buffer 3

100 mL of 50mM Acetate Buffer pH 4.5

Calculations

Amount of acid component

M=nV

(1.8M)=(0.00307mol)(V)

V=1.67mL

Amount base component

m=MM*n

m=136.08g/mol*0.00192mol

m=0.259g

• Actual measurement = 0.276g
• Actual pH=4.3
• Buffer 4

100 mL of 50mM Acetate Buffer pH 5.5

Calculations

Amount of acid component

M=nV

(1.8M)=(0.00055mol)(V)

V=0.36mL

Amount base component

m=MM*n

m=136.08g/mol*0.0043mol

m=0..591g

• Actual measurement = 0.6143g
• Actual pH=5.46
• Buffer 5

100 mL of 50mM Tris Buffer pH 7.5

Calculations

Amount of Tris

m=0.607g

• Actual mass m=0.6109g

Titrate to pH 7.5 with 1.8M acetic acid

• Actual pH=7.55

Notes

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