An oxide of iron contains 69.9% icon and 30.1% oxygen by mass. Calculate the empirical mass and molecular mass of the oxide.An oxide of iron contains 69.9% icon and 30.1% oxygen by mass. Calculate the empirical mass and molecular mass of the oxide.
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Answer:
Fe:O=69.955.85:30.116=1.25:1.88=1:1.5=2:3. ∴ Its empirical formula is Fe2O3.
Verified answer
Answer:
To calculate the empirical mass of the oxide, we need to determine the ratio of iron to oxygen in the compound.
Assuming a 100g sample of the oxide, we have:
- 69.9g of iron
- 30.1g of oxygen
Next, we convert these masses to moles using the molar masses of iron and oxygen:
- Molar mass of iron (Fe) = 55.85 g/mol
- Molar mass of oxygen (O) = 16.00 g/mol
The number of moles of iron is calculated as:
69.9g Fe * (1 mol Fe / 55.85 g Fe) = 1.25 mol Fe
The number of moles of oxygen is calculated as:
30.1g O * (1 mol O / 16.00 g O) = 1.88 mol O
To find the empirical formula, we divide the number of moles by the smallest number of moles (in this case, 1.25 mol Fe):
Fe: 1.25 mol / 1.25 mol = 1
O: 1.88 mol / 1.25 mol = 1.504
Rounding these values to the nearest whole number, we get the empirical formula FeO.
To calculate the empirical mass, we add up the molar masses of iron and oxygen:
Empirical mass = Molar mass of Fe + Molar mass of O
Empirical mass = 55.85 g/mol + 16.00 g/mol
Empirical mass = 71.85 g/mol
The molecular mass of the oxide is equal to its empirical mass since the empirical formula already represents the actual molecular formula.
Therefore, the empirical mass and molecular mass of the oxide are both approximately 71.85 g/mol.