Model Answer
0 min readIntroduction
Iron is one of the most abundant elements in the Earth’s crust and is a crucial component of many minerals. Magnetite (Fe₃O₄) and hematite (Fe₂O₃) are two of the most important iron ores, serving as primary sources for iron production. While both contain iron, their chemical compositions differ, leading to variations in their iron content. Determining the weight percentage of iron in each mineral is essential for evaluating their economic viability and understanding their geological significance. This answer will calculate and compare the iron concentration in magnetite and hematite using their respective chemical formulas and atomic weights.
Chemical Formulas and Molecular Weights
First, let's establish the chemical formulas and calculate the molecular weights of magnetite and hematite.
Magnetite (Fe₃O₄)
The chemical formula for magnetite is Fe₃O₄. To calculate its molecular weight:
- Atomic weight of Fe = 56
- Atomic weight of O = 16
- Molecular weight of Fe₃O₄ = (3 x 56) + (4 x 16) = 168 + 64 = 232
Hematite (Fe₂O₃)
The chemical formula for hematite is Fe₂O₃. To calculate its molecular weight:
- Atomic weight of Fe = 56
- Atomic weight of O = 16
- Molecular weight of Fe₂O₃ = (2 x 56) + (3 x 16) = 112 + 48 = 160
Calculating Iron Concentration (wt.%)
Now, we will calculate the weight percentage of iron in each mineral.
Magnetite (Fe₃O₄)
Weight of iron in one molecule of Fe₃O₄ = 3 x 56 = 168
Iron concentration (wt.%) = (Weight of iron / Molecular weight of Fe₃O₄) x 100
Iron concentration (wt.%) = (168 / 232) x 100 ≈ 72.37%
Hematite (Fe₂O₃)
Weight of iron in one molecule of Fe₂O₃ = 2 x 56 = 112
Iron concentration (wt.%) = (Weight of iron / Molecular weight of Fe₂O₃) x 100
Iron concentration (wt.%) = (112 / 160) x 100 = 70%
Comparison
Based on the calculations:
| Mineral | Iron Concentration (wt.%) |
|---|---|
| Magnetite (Fe₃O₄) | 72.37% |
| Hematite (Fe₂O₃) | 70% |
Therefore, magnetite contains more iron (72.37%) than hematite (70%) by weight.
Conclusion
In conclusion, through stoichiometric calculations based on their chemical formulas and atomic weights, we have determined that magnetite (Fe₃O₄) possesses a higher iron concentration (approximately 72.37%) compared to hematite (Fe₂O₃) which has an iron concentration of 70%. This difference in iron content is a significant factor in evaluating the economic viability of these minerals as iron ores. Understanding the chemical composition of minerals is fundamental to geological and metallurgical studies.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.