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%.