Respuesta :
Let's find the empirical formula step wise.
1st step - Get the mass of each element of the compound.
Here, the masses of K and O are given in grams.
Mass of K = 32.3 g
Mass of O = 6.61 g
2nd step - Get the molar mass of each element .
Molar mass of K = 39.10 g/mol
Molar mass of O = 16.00 g/mol
3rd step - find the moles of each element.
We know that,
moles (mol) = mass (g) / molar mass(g/mol)
Let's apply that formula to find the moles.
Moles of K = 32.3 g / 39.10 g/mol = 0.83 mol
Moles of O = 6.61 g / 16.00 g/mol = 0.41 mol
4th step - find the lowest number of moles
According to the above calculations, O has the lowest number of moles as 0.41 mol.
5th step - Divide the moles of each element by lowest number of moles to get the mole ratio between elements.
K = 0.83 mol / 0.41 mol = 2.02 = 2
O = 0.41 mol / 0.41 mol = 1
6th step - write the formula by using mole ratios.
Empirical formula = K₂O₁ = K₂O
To calculate the empirical formula of a compound, we have to follow some steps:
Step 1: Calculate the number of moles of K and O.
For this we need to know the molar mass of K and O.
Molar mass of K=39.0983 g/mol
Molar mass of O=16 g/mol
Given mass of K= 32.3 g
Given mass of O= 6.61 g
Number of moles=Mass /molar mass
So, Number of moles of O=Mass /molar mass
=6.61/16
=0.41
Number of moles of K =Mass /molar mass
=32.3/39
=0.82
Step 2: Find the lowest number of moles and divide each element's moles by it:
Here the lowest number of moles are of oxygen(O) so dividing each element's moles by its mole number will give:
K =0.82/0.41
= 2
O = 0.41/0.41
= 1
So the empirical formula of the compound should be:
K₂O.
