The molar mass of iron (iii) oxide (fe2o3) is 159.7 g/mol. what is the correct way to write the molar mass of iron oxide as a conversion factor? startfraction 159.7 grams upper f e subscript 2 upper o subscript 3 over 159.7 moles upper f e subscript 2 upper o subscript 3 endfraction. startfraction 1 gram upper f e subscript 2 upper o subscript 3 over 159.7 moles upper f e subscript 2 upper o subscript 3 endfraction. startfraction 159.7 grams upper f e subscript 2 upper o subscript 3 over 1 mole upper f e subscript 2 upper o subscript 3 endfraction. startfraction 1 gram upper f e subscript 2 upper o subscript 3 over 1 mole upper f e subscript 2 upper o subscript 3 endfraction.
The Correct Answer and Explanation is :
The correct way to write the molar mass of iron(III) oxide (Fe₂O₃) as a conversion factor is:
[
\frac{159.7 \, \text{grams} \, \text{Fe}_2\text{O}_3}{1 \, \text{mole} \, \text{Fe}_2\text{O}_3}
]
Explanation
Molar mass is defined as the mass of one mole of a substance, typically expressed in grams per mole (g/mol). For iron(III) oxide, the molar mass is calculated by adding the atomic masses of its constituent elements: iron (Fe) and oxygen (O).
Iron has an atomic mass of approximately 55.85 g/mol, and oxygen has an atomic mass of about 16.00 g/mol. In Fe₂O₃, there are two iron atoms and three oxygen atoms. The calculation of the molar mass is as follows:
[
\text{Molar Mass of Fe}_2\text{O}_3 = (2 \times 55.85 \, \text{g/mol}) + (3 \times 16.00 \, \text{g/mol}) = 111.70 \, \text{g/mol} + 48.00 \, \text{g/mol} = 159.70 \, \text{g/mol}
]
This results in the total molar mass of Fe₂O₃ being 159.7 g/mol. When we write this as a conversion factor, we typically express it in a way that allows for the conversion of grams of the substance to moles, or vice versa.
The format (\frac{159.7 \, \text{grams} \, \text{Fe}_2\text{O}_3}{1 \, \text{mole} \, \text{Fe}_2\text{O}_3}) indicates that for every mole of Fe₂O₃, there are 159.7 grams. This is essential for stoichiometric calculations in chemistry, where we need to convert between mass and amount of substance to understand reactions quantitatively. The other options either incorrectly express the relationship or do not accurately represent the conversion factor necessary for calculations involving Fe₂O₃.
In summary, using the correct molar mass conversion factor is crucial for accurately performing calculations in chemistry related to the quantities of substances involved in reactions.