A 18.46 g sample of a compound contains 5.89 g potassium (K), 5.34 g chlorine (Cl), and oxygen (O). Calculate the empirical formula.
the answer is: KClO3?
mols K = grams/atomic mass K = ?
mols Cl = grams/atomic mass Cl = ?
mols O = grams/atomic mass O = ?
(Note: mass O = 18.46-g K - g Cl)
Now find the ratio of the elements to one another with the smallest number being 1.00. The easy way to do that is to divide the smallest number by itself (thereby getting 1.0000000); then divide the other numbers by the same small number. Round to whole numbers and that should give you the empirical formula.
yes
To determine the empirical formula of a compound, we need to find the simplest whole-number ratio of the elements present in the compound.
First, let's find the molar masses of each element:
- Potassium (K) has a molar mass of 39.10 g/mol.
- Chlorine (Cl) has a molar mass of 35.45 g/mol.
- Oxygen (O) has a molar mass of 16.00 g/mol.
Next, we need to determine the number of moles for each element:
- Number of moles of K = mass of K / molar mass of K
= 5.89 g / 39.10 g/mol
= 0.1504 mol
- Number of moles of Cl = mass of Cl / molar mass of Cl
= 5.34 g / 35.45 g/mol
= 0.1505 mol
- Number of moles of O = Mass of compound - (moles of K + moles of Cl)
= 18.46 g - (0.1504 mol + 0.1505 mol)
= 18.46 g - 0.3009 mol
= 18.1591 g / 16.00 g/mol
= 1.134 mol
Next, we need to find the simplest whole-number ratio of moles by dividing each of the moles by the smallest number of moles:
- K:O ratio = 0.1504 mol / 0.1504 mol = 1
- Cl:O ratio = 0.1505 mol / 0.1504 mol ≈ 1
The empirical formula is KClO, where the subscripts indicate the number of atoms of each element in the formula.