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The iron content in multivitamin tablets was determined using atomic absorption spectroscopy - VCE - SSCE Chemistry - Question 6 - 2012 - Paper 1
Question 6
The iron content in multivitamin tablets was determined using atomic absorption spectroscopy. The absorbances of four standards were measured. The absorbance of eac... show full transcript
Worked Solution & Example Answer:The iron content in multivitamin tablets was determined using atomic absorption spectroscopy - VCE - SSCE Chemistry - Question 6 - 2012 - Paper 1
Step 1
ii. Determine the average iron content, in milligrams, of the multivitamin tablets.
Answer
To determine the average iron content:
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Extract Absorbances for Tablets: The absorbances of the tablets were measured as follows:
- Tablet 1: 0.39
- Tablet 2: 0.42
- Tablet 3: 0.45
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Use the Calibration Graph: Using the calibration graph established in part i, determine the concentrations corresponding to each absorbance:
- For an absorbance of 0.39, the corresponding concentration can be interpolated to be approximately 30 mg/L.
- For an absorbance of 0.42, the concentration is approximately 36 mg/L.
- For an absorbance of 0.45, the concentration is approximately 40 mg/L.
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Calculate Average Concentration: The average concentration can be calculated as follows: ext{Average} = rac{30 + 36 + 40}{3} = 35.33 ext{ mg/L}
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Convert to Milligrams: Since each tablet was diluted in 100 mL, the total iron content in each tablet can be estimated to be:
Thus, the average iron content of the multivitamin tablets is approximately 3.53 mg.
Step 2
i. Which part of the electromagnetic spectrum does this technique use?
Answer
The technique of Atomic Absorption Spectroscopy (AAS) primarily uses the visible part of the electromagnetic spectrum. It involves measuring the absorbance of specific wavelengths of light as they pass through the sample.
Step 3
ii. How does this part of the electromagnetic spectrum interact with matter? What information does this spectroscopic technique provide?
Answer
In AAS, the visible light interacts with electrons in the atoms of the sample, promoting them to higher energy levels. This interaction is quantified by measuring the absorbance, which indicates the concentration of the absorbing species in the sample. The information provided includes the concentration of specific elements in the sample, allowing for trace element analysis.