Question

2. You are performing an iodometric titration of ascorbic acid using a KIO3 standard solution. Suppose that the amount of ascorbic acid in the sample you are about to titrate is 85 mg. Calculate the mass (g) of KIO3 required to make 100.0 mL of the standard solution such that about 25 mL of it is used to completely react with the ascorbic acid present in the sample to be titrated. The formula weight of ascorbic acid is 176.12 g/mol. The formula weight of potassium iodate is 214.00 g/mol?

Answer 1

To calculate the mass of KIO3 required to make 100.0 mL of the standard solution, we need to use stoichiometry and the given information. Using the given mass of ascorbic acid and its formula weight, we can calculate the number of moles, which is equal to the number of moles of KIO3 required. Finally, we can calculate the mass of KIO3 using the moles of KIO3 and its formula weight.

Step-by-step explanation:

To calculate the mass of KIO3 required to make 100.0 mL of the standard solution, we need to use stoichiometry and the given information. First, let's calculate the number of moles of ascorbic acid in the sample. We have 85 mg of ascorbic acid, which is equivalent to 0.085 g. Using the formula weight of ascorbic acid (176.12 g/mol), we can calculate the number of moles:

moles of ascorbic acid = mass of ascorbic acid / formula weight of ascorbic acid

moles of ascorbic acid = 0.085 g / 176.12 g/mol = 0.000483 mol

Since the reaction between ascorbic acid and KIO3 has a 1:1 stoichiometric ratio, we need the same number of moles of KIO3 as ascorbic acid. Therefore, we need 0.000483 mol of KIO3.

Now, let's calculate the mass of KIO3:

mass of KIO3 = moles of KIO3 × formula weight of KIO3

mass of KIO3 = 0.000483 mol × 214.00 g/mol = 0.1035 g

Therefore, the mass of KIO3 required to make 100.0 mL of the standard solution is 0.1035 g.