Amino acid solution was made by taking 3.58 g of the dry amino acid and making it up to 1.00L in water. A 25.0 mL sample was taken and titrated with NaOH of concentration of 0.0493M, with the first equivalence point at 18.15 mL and the second equivalence point at 32.05 mL. What is the molecular weight of the amino acid?

To determine the molecular weight of the amino acid, we need to calculate the number of moles of the amino acid used to make the solution, and then use that information to find the molecular weight.

Step 1: Calculate the number of moles of amino acid in the solution.

First, we need to calculate the concentration of the amino acid solution. We can use the formula:

concentration (in mol/L) = moles/volume (in L)

We know that the volume of the amino acid solution is 1.00 L, and we used 3.58 g of the amino acid to make it. To find the moles, we need to convert grams of amino acid to moles.

The molecular weight (MW) of the amino acid is calculated using the formula:

MW = mass/number of moles

Therefore, the number of moles (n) can be calculated as:

n = mass/MW

Step 2: Calculate the molecular weight of the amino acid.

To calculate the molecular weight, we'll rearrange the formula:

MW = mass/number of moles

Given:
Volume of amino acid solution (V) = 1.00 L
Mass of amino acid (m) = 3.58 g
First equivalence point volume of NaOH (V1) = 18.15 mL
Second equivalence point volume of NaOH (V2) = 32.05 mL
Concentration of NaOH (C) = 0.0493 M

Now, let's calculate the number of moles of the amino acid:

n = mass/MW

Substituting the given values:

n = 3.58 g/MW

To determine the molecular weight, we need to first calculate the moles of NaOH used in each titration.

Moles of NaOH used at first equivalence point (n1) = C * V1
Moles of NaOH used at second equivalence point (n2) = C * V2

Finally, we can calculate the molecular weight using the equation:

MW = mass/number of moles

By substituting the given values, we can now find the molecular weight of the amino acid.