Tris is a molecule that can be used to prepare buffers for biochemical experiments. It exists in two forms: Tris (a base) and TrisH (an acid). The MW of Tris base is 121.14 g/mol; the MW of TrisH is 157.6 g/mol (the extra weight is due to the Cl- counterion that is present in the acid). The Ka of the acid is 8.32 X 10-9. Assume that you have TrisH in solid form (a powder), unlimited 1M HCl, unlimited 1 M NaOH and an unlimited supply of distilled water. How would you prepare 1 L of a 0.02 M Tris Buffer, pH

Solution :

The reaction :

We have

Clearing x, we have moles of acid

Now to reach pH = , we must have an concentration of

          moles of base

We must add enough NaOH of 1 M to neutralize the acid calculated above and also add the calculated base.

                moles

Vol

                 = 0.0135 L

Tris mass

                        = 3.152 g

To prepare the said solution we must mix

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in chemistry, a solution’s concentration is how much of a dissolvable substance, known as a solute, is mixed with another substance, called the solvent. the standard formula is c = m/v, where c is the concentration, m is the mass of the solute dissolved, and v is the total volume