- Use the balanced reaction below to calculate the moles of Vitamin C used: Vitamin C + NaOH –> sodium ascorbate + H20
- calculate the mass of vitamin C present in one titration
- add up the masses of vitamin C from each trial to determine total vitamin C content for both tablets
- calculate the mass of vitamin C in one tablet
- calculate the mass % of vitamin C in one tablet
My given data:
from stock bottles: vitamin C tablet = 500mg
NaOH: 0.09603
mass of tablets = 1.34g
Trial 1: mass of powder 0.29g, NaOH used 17.89mL
Trial 2: mass of powder .78g, NaOH used 19.73mL
Trial 3: mass of powder .40g, NaOH used 31.80mL
The Correct Answer and Explanation is :
To solve this problem, we need to go through each step systematically:
1. Balanced Reaction
The balanced reaction between Vitamin C (ascorbic acid) and NaOH is:
[
\text{Vitamin C} + \text{NaOH} \rightarrow \text{sodium ascorbate} + H_2O
]
From this reaction, we know that one mole of Vitamin C reacts with one mole of NaOH.
2. Calculate the Moles of Vitamin C Used
To calculate the moles of Vitamin C used, we first need to determine the moles of NaOH used in each trial. The molarity (M) of NaOH is given as 0.09603 M, and the volume (V) is given in milliliters, so we can use the formula:
[
\text{moles of NaOH} = M \times V
]
Note: Convert volume from mL to L by dividing by 1000.
For each trial:
Trial 1:
[
\text{moles of NaOH} = 0.09603 \, \text{M} \times \frac{17.89}{1000} \, \text{L} = 0.001717 \, \text{mol}
]
Trial 2:
[
\text{moles of NaOH} = 0.09603 \, \text{M} \times \frac{19.73}{1000} \, \text{L} = 0.001893 \, \text{mol}
]
Trial 3:
[
\text{moles of NaOH} = 0.09603 \, \text{M} \times \frac{31.80}{1000} \, \text{L} = 0.00305 \, \text{mol}
]
Since the molar ratio between Vitamin C and NaOH is 1:1, the moles of Vitamin C used will be the same as the moles of NaOH.
3. Calculate the Mass of Vitamin C in One Titration
To calculate the mass of Vitamin C, we use the molar mass of Vitamin C, which is approximately 176.12 g/mol. The formula is:
[
\text{mass of Vitamin C} = \text{moles of Vitamin C} \times \text{molar mass of Vitamin C}
]
Trial 1:
[
\text{mass of Vitamin C} = 0.001717 \, \text{mol} \times 176.12 \, \text{g/mol} = 0.302 \, \text{g}
]
Trial 2:
[
\text{mass of Vitamin C} = 0.001893 \, \text{mol} \times 176.12 \, \text{g/mol} = 0.333 \, \text{g}
]
Trial 3:
[
\text{mass of Vitamin C} = 0.00305 \, \text{mol} \times 176.12 \, \text{g/mol} = 0.537 \, \text{g}
]
4. Add up the Masses of Vitamin C from Each Trial
Total mass of Vitamin C for both tablets:
[
0.302 \, \text{g} + 0.333 \, \text{g} + 0.537 \, \text{g} = 1.172 \, \text{g}
]
5. Calculate the Mass of Vitamin C in One Tablet
Now, we need to find the mass of Vitamin C in one tablet. The total mass of the two tablets is 1.34 g, and the mass of Vitamin C from both tablets is 1.172 g. Thus, the mass of Vitamin C in one tablet is:
[
\text{mass of Vitamin C in one tablet} = \frac{1.172 \, \text{g}}{2} = 0.586 \, \text{g}
]
6. Calculate the Mass % of Vitamin C in One Tablet
Finally, to calculate the mass percentage of Vitamin C in one tablet, we use the formula:
[
\text{Mass \% of Vitamin C} = \left( \frac{\text{mass of Vitamin C in one tablet}}{\text{mass of one tablet}} \right) \times 100
]
[
\text{Mass \% of Vitamin C} = \left( \frac{0.586 \, \text{g}}{1.34 \, \text{g}} \right) \times 100 = 43.7\%
]
Final Results:
- The moles of Vitamin C used in each trial are: 0.001717 mol (Trial 1), 0.001893 mol (Trial 2), 0.00305 mol (Trial 3).
- The masses of Vitamin C in each trial are: 0.302 g (Trial 1), 0.333 g (Trial 2), 0.537 g (Trial 3).
- The total mass of Vitamin C from both tablets is 1.172 g.
- The mass of Vitamin C in one tablet is 0.586 g.
- The mass % of Vitamin C in one tablet is 43.7%.
This means that 43.7% of the mass of the tablet is Vitamin C.