Find the formula for the compound that contains 72.4% iron and 27.6% oxygen.
To find the formula for the compound that contains 72.4% iron (Fe) and 27.6% oxygen (O), we first need to determine the ratio of iron to oxygen in the compound by converting the percentages to moles.
1. Convert the percentages to moles:
For iron (Fe):
Molar mass of iron (Fe) = 55.845 g/mol
Moles of iron = (72.4 g Fe) / (55.845 g/mol) = 1.298 mol Fe
For oxygen (O):
Molar mass of oxygen (O) = 16.00 g/mol
Moles of oxygen = (27.6 g O) / (16.00 g/mol) = 1.725 mol O
2. Divide the number of moles by the smallest number of moles to find the ratio:
Fe:O = 1.298 mol Fe / 1.298 mol Fe = 1
O:Fe = 1.725 mol O / 1.298 mol Fe = 1.33
3. Since we need to find a whole number ratio, we can multiply these values by 3 to get a whole number ratio:
Fe:O = 1 × 3 = 3
O:Fe = 1.33 × 3 = 4
4. Write the chemical formula using the ratio:
The chemical formula for the compound with 72.4% iron and 27.6% oxygen is Fe3O4.
To find the formula for the compound containing iron and oxygen, you need to determine the ratio of the elements present in the compound. The ratios can be determined by dividing the mass or moles of each element by their respective atomic masses.
Let's assume we have 100 grams of the compound. This means that there are 72.4 grams of iron and 27.6 grams of oxygen.
1. Convert the mass of each element to moles:
To convert the mass to moles, divide the mass of each element by its molar mass. The molar mass of iron (Fe) is 55.85 g/mol, and the molar mass of oxygen (O) is 16.00 g/mol.
Moles of iron = 72.4 g / 55.85 g/mol = 1.297 mol
Moles of oxygen = 27.6 g / 16.00 g/mol = 1.725 mol
2. Determine the simplest whole number ratio:
Divide the number of moles of each element by the smallest number of moles to find the simplest whole number ratio.
Moles of iron (Fe) = 1.297 mol / 1.297 mol = 1 mol
Moles of oxygen (O) = 1.725 mol / 1.297 mol = 1.333 mol
Since the ratio is not a whole number, we can multiply it by a common factor to get whole numbers. In this case, multiplying by 3 will work.
Moles of iron (Fe) = 1 mol x 3 = 3
Moles of oxygen (O) = 1.333 mol x 3 = 4
Therefore, the simplest whole number ratio is 3:4. This means that the formula for the compound containing 72.4% iron and 27.6% oxygen is Fe3O4.
Take a 100 g sample which will give you
72.4 g Fe and 27.6g O.
Now convert g of each to moles. moles = grams/molar mass.
Find the ratio of the elements tlo each other using small whole numbers with the lowest being 1.00. The easy way to do this is to divide the smaller number by itself which assures you of 1.00 for that element. Divide the other number by the same small number and round both to even numbers BUT don't round too much (not over 0.1 or so). For example, if you get Fe1O1.5, this is a ratio of 2:3. If you obtain numbers that can'tg be rounded, multiply by whole numbers until you get numbers that can be rounded for both. Post your work if need additional help.