Respuesta :
Answer: The empirical formula of the compound is [tex]KMnO_4[/tex]
Explanation:
The empirical formula is the chemical formula of the simplest ratio of the number of atoms of each element present in a compound.
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
Let the mass of the compound be 100 g
Given values:
% of K = 24.7%
% of Mn = 34.76%
% of O = 40.50%
Mass of K = 24.7 g
Mass of Mn = 34.76 g
Mass of O = 40.50 g
To calculate the empirical formula of a compound, few steps need to be followed:
- Step 1: Calculating the number of moles of each element
We know:
Molar mass of K = 39.10 g/mol
Molar mass of Mn = 54.94 g/mol
Molar mass of O = 16 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of K}=\frac{24.7g}{39.10g/mol}=0.632 mol[/tex]
[tex]\text{Moles of Mn}=\frac{34.76g}{54.94g/mol}=0.633 mol[/tex]
[tex]\text{Moles of O}=\frac{40.50g}{16g/mol}=2.53 mol[/tex]
- Step 2: Calculating the mole fraction of each element by dividing the calculated moles by the least calculated number of moles that is 0.632 moles
[tex]\text{Mole fraction of K}=\frac{0.632}{0.632}=1[/tex]
[tex]\text{Mole fraction of Mn}=\frac{0.633}{0.632}=1[/tex]
[tex]\text{Mole fraction of O}=\frac{2.53}{0.632}=4[/tex]
- Step 3: Writing the mole fraction as the subscripts of each of the element
The empirical formula of the compound becomes [tex]K_1Mn_1O_4=KMnO_4[/tex]
Hence, the empirical formula of the compound is [tex]KMnO_4[/tex]
The empirical formula of the compound is KMnO₄
Data obtained from the question
- Potassium (K) = 24.74%
- Manganese (Mn) = 34.76%
- Oxygen (O) = 40.50%
- Empirical formula =?
How to determine the empirical formula
Divide by their molar mass
K = 24.74 / 39 = 0.634
Mn = 34.76 / 55 = 0.632
O = 40.50 / 16 = 2.531
Divide by the smallest
K = 0.634 / 0.632 = 1
Mn = 0.632 / 0.632 = 1
O = 2.531 / 0.632 = 4
Therefore, the empirical formula of the compound is KMnO₄
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