While trace impurities of iron and chromium in natural corundum form the gemstones ruby and sapphire, they are basically a binary compound of aluminum and oxygen, with 52.9% Al. Find the empirical formula and give the chemical name for corundum.
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See your post below. The formula is Al2O3.
To determine the empirical formula and chemical name of corundum, we need to use the given information.
Step 1: Convert the percentages to grams.
Since we are given that 52.9% of corundum is aluminum (Al), we can assume that the other 47.1% is oxygen (O).
Assuming we have 100 grams of corundum:
- Aluminum (Al) = 52.9 grams (52.9% of 100 grams)
- Oxygen (O) = 47.1 grams (47.1% of 100 grams)
Step 2: Convert the grams to moles.
To convert grams to moles, divide the grams by the molar mass of each element.
- Aluminum (Al): The molar mass of Al is 26.98 g/mol, so the number of moles of Al is 52.9 g / 26.98 g/mol ≈ 1.96 mol (rounded to two decimal places).
- Oxygen (O): The molar mass of O is 16.00 g/mol, so the number of moles of O is 47.1 g / 16.00 g/mol ≈ 2.94 mol (rounded to two decimal places).
Step 3: Divide by the smallest number of moles.
To find the empirical formula, we need to determine the simplest whole-number ratio between the moles of each element by dividing them by the smallest number of moles.
Dividing both values by 1.96 (the smallest number of moles):
- Aluminum (Al): 1.96 mol / 1.96 mol = 1
- Oxygen (O): 2.94 mol / 1.96 mol ≈ 1.50 (rounded to two decimal places)
Since we need to simplify the ratio to whole numbers, we can multiply both values by 2:
- Aluminum (Al) = 2
- Oxygen (O) = 3
The empirical formula of corundum is therefore Al2O3.
Step 4: Determine the chemical name.
Corundum is the mineral name for the gemstones ruby and sapphire. The chemical name for the compound with the empirical formula Al2O3 is aluminum oxide.
In conclusion, the empirical formula for corundum is Al2O3, and its chemical name is aluminum oxide.