How many grammes Tn3 and Tn3 HCL are need to make up 500ml of 1m Tn3 buffer with a PH of 8.0?
Pka of Tn3 =8.3
MW of Tn3 =121
MW of Tn3=157
To calculate the amount of Tn3 and Tn3 HCl needed to make 500 ml of 1 M Tn3 buffer with a pH of 8.0, we need to consider the pKa of Tn3 and the desired pH of the buffer solution.
Here are the steps to calculate the amount of Tn3 and Tn3 HCl required:
Step 1: Calculate the ratio of protonated and deprotonated forms of Tn3 at pH 8.0.
- The pKa of Tn3 is given as 8.3, which means that at pH 8.0, the ratio of protonated to deprotonated forms can be calculated using the Henderson-Hasselbalch equation:
pH = pKa + log ([A-]/[HA])
8.0 = 8.3 + log ([A-]/[HA])
[A-]/[HA] = antilog(8.3 - 8.0) = 10^(-0.3)
Step 2: Determine the amount of Tn3 needed.
- Tn3 is protonated in the form of HA, and we want a 1 M concentration of Tn3 in the buffer solution. Therefore, the amount of Tn3 in grams can be calculated as follows:
Amount of Tn3 (g) = Concentration (M) x Volume (L) x Molecular Weight (g/mol)
= 1 M x 0.5 L x 121 g/mol
Step 3: Determine the amount of Tn3 HCl needed.
- Tn3 HCl is deprotonated and correlates with the A- (conjugate base) form required for the desired pH. To calculate the amount of Tn3 HCl in grams:
Amount of Tn3 HCl (g) = Amount of Tn3 (g) x [A-]/[HA]
= Amount of Tn3 (g) x 10^(-0.3)
Now you can substitute the values mentioned in the question to get the final amounts of Tn3 and Tn3 HCl needed.