The hydrolysis of one mole of sulphate ester produces one mole of protons.In a reaction tube containing 1.0ml of 0.02M TRIS buffer,pH8.08,sulphate ester was incubated with sulphatase for 10 min.At the end of reaction,the pH was reduced to 7.97.Calculated the amount of sulphate ester that has been hydrolyzed in 10 min.give your answer in micromoles of sulphate ester.
I would do something like this. Check my thinking. If the solution is 1 mL x 0.02 M TRIS buffer and the pH is 8.08, that means equal moles TRIS and TRIS*HCl (substitute into the HH equation and base/acid = 1 if you don't see this right away). 1 mL x 0.02 M = 0.02 mmoles buffer or 0.01 mmoles TRIS and 0.01 mmoles TRIS*HCl
...............TRIS + H^+ ==> TRIS*HCl
initial mmoles..0.01...0....0.01 mmole
change...........-x...+x.......+x
final..........0.01-x...+x......0.01+x
Substitute into the HH equation and solve for x.
7.97 = 8.08 + log [(0.01-x)/(0.01+x)]
x will be in mmoles H^+ which will be the same as mmoles of the ester hydrolyzed. You will need to change to micromoles ester hydrolyzed.
To calculate the amount of sulphate ester that has been hydrolyzed in 10 minutes, we need to use the change in pH and information about the buffer and concentration.
Given:
- Volume of TRIS buffer = 1.0 mL = 0.001 L
- Concentration of TRIS buffer = 0.02 M
- Initial pH = 8.08
- Final pH after reaction = 7.97
The TRIS buffer is used to maintain the pH of the solution during the reaction. The buffer capacity is determined by the concentration of the buffer and the change in pH.
First, we need to calculate the change in H+ concentration (Δ[H+]) by using the change in pH:
ΔpH = Final pH - Initial pH
ΔpH = 7.97 - 8.08
ΔpH = -0.11
To convert ΔpH into Δ[H+], we use the formula:
[H+] = 10^(-pH)
[H+]initial = 10^(-Initial pH)
[H+]final = 10^(-Final pH)
Δ[H+] = [H+]final - [H+]initial
Now, let's calculate Δ[H+] and Δ[Sulphate ester]:
Δ[H+] = 10^(-7.97) - 10^(-8.08)
Next, we need to use the stoichiometric ratio given in the problem: one mole of sulphate ester produces one mole of protons.
Since the Δ[H+] concentration is in moles per liter (M), we can directly equate Δ[H+] to Δ[Sulphate ester] in micromoles (μmol).
Δ[H+] = Δ[Sulphate ester]
Now, substitute the calculated Δ[H+] value into the equation to find Δ[Sulphate ester]:
Δ[Sulphate ester] = Δ[H+] = 10^(-7.97) - 10^(-8.08)
Finally, convert Δ[Sulphate ester] into micromoles by multiplying by the volume of the buffer used:
Δ[Sulphate ester] in μmol = Δ[Sulphate ester] * Volume of TRIS buffer
Plug in the values and calculate the result.