A sample of hematite contains 34.97 g of iron and 15.03 g of oxygen. What I’d the empirical formula?
To determine the empirical formula, we need to find the ratio of the number of atoms of each element present in the compound.
1. Convert the mass of each element into moles:
Given:
Mass of iron (Fe) = 34.97 g
Mass of oxygen (O) = 15.03 g
Molar mass of iron (Fe) = 55.85 g/mol
Molar mass of oxygen (O) = 16.00 g/mol
Number of moles of iron (Fe) = mass of iron / molar mass of iron
= 34.97 g / 55.85 g/mol
≈ 0.626 mol
Number of moles of oxygen (O) = mass of oxygen / molar mass of oxygen
= 15.03 g / 16.00 g/mol
≈ 0.939 mol
2. Divide the number of moles of each element by the smallest number of moles calculated. In this case, the smallest number of moles is 0.626, so we divide both the number of moles by this value.
Number of moles of iron (Fe) = 0.626 mol / 0.626 mol
= 1 mol
Number of moles of oxygen (O) = 0.939 mol / 0.626 mol
≈ 1.5 mol
3. Multiply each element's mole ratio by a common factor if necessary to obtain whole numbers.
Going back to the number of moles ratio:
Fe:O = 1:1.5
Multiply by 2 to eliminate fractions:
Fe:O = 2:3
4. Write the empirical formula using the ratio obtained:
Fe2O3
So, the empirical formula of the compound is Fe2O3, which represents hematite.
To determine the empirical formula of hematite, we need to find the ratio of iron to oxygen.
Step 1: Convert the mass of each element into moles.
Since we know the molar mass of iron (Fe) is 55.845 g/mol and the molar mass of oxygen (O) is 15.999 g/mol, we can calculate the number of moles for each element.
Moles of iron (Fe) = mass of iron (34.97 g) / molar mass of iron (55.845 g/mol) ≈ 0.6265 mol
Moles of oxygen (O) = mass of oxygen (15.03 g) / molar mass of oxygen (15.999 g/mol) ≈ 0.9394 mol
Step 2: Determine the simplest whole number ratio of moles.
Divide both moles of iron and oxygen by the smallest number of moles to find the ratio:
Moles of iron (Fe) / 0.6265 mol ≈ 1
Moles of oxygen (O) / 0.6265 mol ≈ 1.5
This gives us a ratio of iron to oxygen of approximately 1:1.5.
Step 3: Convert the ratio to whole numbers.
To convert the ratio to whole numbers, we multiply both sides by 2:
Iron (Fe) = 1 x 2 = 2
Oxygen (O) = 1.5 x 2 = 3
The empirical formula of hematite is Fe2O3, indicating that it contains two atoms of iron and three atoms of oxygen.
To find the empirical formula of a compound, we need to determine the simplest whole number ratio of elements present in the compound.
In this case, we are given the mass of iron (Fe) and oxygen (O) present in the sample of hematite.
Step 1: Convert the mass of each element to moles.
To do this, we need to divide the given mass by the molar mass of each element. The molar mass of iron is 55.85 g/mol and oxygen is 16.00 g/mol.
Number of moles of iron (Fe) = 34.97 g / 55.85 g/mol = 0.626 mol
Number of moles of oxygen (O) = 15.03 g / 16.00 g/mol = 0.939 mol
Step 2: Determine the mole ratio between the elements.
Divide the number of moles of each element by the smallest number of moles. This will give us the simplest, whole number ratio.
Number of moles of iron (Fe) / Smallest number of moles (0.626 mol) = 0.626 mol / 0.626 mol = 1
Number of moles of oxygen (O) / Smallest number of moles (0.626 mol) = 0.939 mol / 0.626 mol = 1.5
Step 3: Write the empirical formula.
The empirical formula is written using subscripts to represent the number of atoms of each element in the compound.
Based on the mole ratio, the empirical formula of hematite is Fe2O3.