a capsule of vitamin C.. a weak acid, is analyzed by titrating it with 0.425 M sodium hydroxide. it is found that 6.20 Ml of base is required to react with capsule weighing 0.628 g. what is the percentage of vitamin C (C6H8O6) in the capsule?( one mole of vitamin C reacts with two moles of hydroxide ion)?

C + 2NaOH ==> 2H2O + Na2C

How many mols of NaOH are used in the titration? That is M x L = mols NaOH.

Now convert mols NaOH to mols C using the coefficients in the balanced equation.

Convert mols C to grams C. mass C = mols C x molar mass C.

%C = [mass C/mass sample]*100
(Mass of sample is 0.628 grams). I should point out here that if the mass of the capsule and contents is 0.628 g then the percent you calculate will not be the percent C in the material inside the capsule. But that is a problem with the problem and not with the way it is being solved.

73.9%

To find the percentage of vitamin C in the capsule, we need to determine the number of moles of vitamin C present in the sample.

Step 1: Determine the number of moles of sodium hydroxide (NaOH) used.
Given:
Volume of NaOH used = 6.20 mL = 6.20 x 10^-3 L
Concentration of NaOH = 0.425 M

Using the formula: moles = concentration x volume
moles of NaOH = 0.425 M x 6.20 x 10^-3 L
moles of NaOH = 0.002635 mol

Step 2: Calculate the number of moles of vitamin C (C6H8O6) reacted with NaOH.
From the given information, 1 mole of vitamin C reacts with 2 moles of hydroxide ion (OH^-).
Therefore, moles of C6H8O6 = (moles of NaOH) / (2 moles of OH^- per mole of C6H8O6)
moles of C6H8O6 = 0.002635 mol / 2
moles of C6H8O6 = 0.0013175 mol

Step 3: Determine the molar mass of vitamin C (C6H8O6).
Molar mass of C6H8O6 = (6 x atomic mass of Carbon) + (8 x atomic mass of Hydrogen) + (6 x atomic mass of Oxygen)
Molar mass of C6H8O6 = (6 x 12.01 g/mol) + (8 x 1.01 g/mol) + (6 x 16.00 g/mol)
Molar mass of C6H8O6 = 176.12 g/mol

Step 4: Calculate the mass of vitamin C in the capsule.
Given:
Mass of capsule = 0.628 g

Mass of C6H8O6 = (moles of C6H8O6) x (molar mass of C6H8O6)
Mass of C6H8O6 = 0.0013175 mol x 176.12 g/mol
Mass of C6H8O6 = 0.232 g

Step 5: Calculate the percentage of vitamin C in the capsule.
Percentage of C6H8O6 = (Mass of C6H8O6 / Mass of capsule) x 100
Percentage of C6H8O6 = (0.232 g / 0.628 g) x 100
Percentage of C6H8O6 = 36.94%

Therefore, the percentage of vitamin C (C6H8O6) in the capsule is approximately 36.94%.

To calculate the percentage of vitamin C in the capsule, we need to determine the number of moles of vitamin C and the total mass of the capsule.

First, let's calculate the number of moles of sodium hydroxide (NaOH) that reacted with the vitamin C capsule. We can use the molarity and volume of the sodium hydroxide solution:

Moles of NaOH = Molarity × Volume
Moles of NaOH = 0.425 mol/L × 0.00620 L
Moles of NaOH = 0.00263 mol

According to the given information, one mole of vitamin C reacts with two moles of hydroxide ions (OH-). Therefore, the number of moles of vitamin C is half of the number of moles of sodium hydroxide:

Moles of vitamin C = 0.00263 mol / 2
Moles of vitamin C = 0.00132 mol

Now, let's calculate the mass of the vitamin C in the capsule. We can use the molar mass of vitamin C:

Molar mass of vitamin C (C6H8O6) = 6 × atomic mass of carbon (C) + 8 × atomic mass of hydrogen (H) + 6 × atomic mass of oxygen (O)

From the periodic table, we find that the atomic masses are approximately:

Atomic mass of carbon (C) ≈ 12.01 g/mol
Atomic mass of hydrogen (H) ≈ 1.01 g/mol
Atomic mass of oxygen (O) ≈ 16.00 g/mol

Molar mass of vitamin C = 6 × 12.01 g/mol + 8 × 1.01 g/mol + 6 × 16.00 g/mol
Molar mass of vitamin C ≈ 176.12 g/mol

Now, we can calculate the mass of the vitamin C in the capsule:

Mass of vitamin C = Moles of vitamin C × Molar mass of vitamin C
Mass of vitamin C = 0.00132 mol × 176.12 g/mol
Mass of vitamin C ≈ 0.232 g

Finally, to find the percentage of vitamin C in the capsule, divide the mass of vitamin C by the total mass of the capsule (0.628 g) and multiply by 100:

Percentage of vitamin C = (Mass of vitamin C / Total mass of capsule) × 100
Percentage of vitamin C = (0.232 g / 0.628 g) × 100
Percentage of vitamin C ≈ 36.94%

Therefore, the percentage of vitamin C in the capsule is approximately 36.94%.