A student titrated 10.00mL aliquots of her unknown amino acid solution with standard 0.1521M NaOH and with 0.0986M HCl. Inflection points were determined in the graphs after 3.29mL of HCl and 18.61mL of NaOH were added. Calculate the concentration of the amino acid
10(x)= MaVaMbVb
or
10x=.1521 *.0986 *3.29 *18.61
To calculate the concentration of the amino acid, we need to use the concept of equivalent points in the titration curves.
1. Calculate the number of moles of NaOH added:
Moles of NaOH = Volume of NaOH added (in L) * Concentration of NaOH (in M)
Moles of NaOH = 0.01861 L * 0.1521 M
2. Calculate the number of moles of HCl added:
Moles of HCl = Volume of HCl added (in L) * Concentration of HCl (in M)
Moles of HCl = 0.00329 L * 0.0986 M
3. Determine the stoichiometric ratio between NaOH and the amino acid.
This information is not provided in the given question. It is important to know the stoichiometry of the reaction in order to calculate the concentration of the amino acid accurately.
4. Once the stoichiometric ratio is known, use it to calculate the number of moles of the amino acid reacted.
Moles of the amino acid reacted = Moles of HCl or NaOH (depending on the stoichiometry)
5. Calculate the concentration of the amino acid:
Concentration of the amino acid (in M) = Moles of the amino acid reacted / Volume of the aliquot (in L)
6. Substitute the values calculated in steps 1 to 5 to find the concentration of the amino acid.
To calculate the concentration of the amino acid, we need to use the information provided by the titration graphs and the equation for the titration reaction.
First, let's define the equation for the titration reaction. In this case, we're titrating the amino acid with both NaOH and HCl. The general equation for an amino acid titration can be represented as:
Amino Acid (AA) + HCl (or NaOH) → Salt of AA + H2O
Based on the given information, we know that the amino acid is reacting with NaOH and HCl, and we have the volumes of NaOH and HCl required to reach the inflection points on the titration graphs.
For the NaOH titration:
- Initial volume of NaOH = 0 mL
- Final volume of NaOH = 18.61 mL
For the HCl titration:
- Initial volume of HCl = 0 mL
- Final volume of HCl = 3.29 mL
Now, we need to find the moles of amino acid reacted with NaOH and HCl separately. To do this, we can use the volume and concentration of the solutions.
For the NaOH titration:
Moles of NaOH used = concentration of NaOH (in mol/L) × volume of NaOH used (in L)
= 0.1521 mol/L × 0.01861 L
For the HCl titration:
Moles of HCl used = concentration of HCl (in mol/L) × volume of HCl used (in L)
= 0.0986 mol/L × 0.00329 L
Since the amino acid reacts in a 1:1 ratio with NaOH and HCl, the moles of amino acid reacted with NaOH and HCl are the same.
Now, let's calculate the moles of the amino acid:
Moles of amino acid = Moles of NaOH = Moles of HCl
Next, we need to find the concentration of the amino acid.
Concentration of amino acid (in mol/L) = Moles of amino acid / Volume of amino acid (in L)
Since the volume of the amino acid is not given, we can assume it to be 10.00 mL.
Volume of amino acid (in L) = 10.00 mL / 1000 mL/L
Finally, we can substitute the values into the equation to calculate the concentration of the amino acid.
Concentration of amino acid (in mol/L) = Moles of amino acid / Volume of amino acid
Based on the calculations, the concentration of the amino acid can be determined.