Answer: The empirical formula of X is [tex]Cr_2O_3[/tex]
Explanation:
If percentage are given then we are taking total mass is 100 grams.
So, the mass of each element is equal to the percentage given.
Mass of Cr = 68.4 g
Mass of O = 31.5 g
Step 1 : convert given masses into moles.
Moles of Cr =[tex]\frac{\text{ given mass of Cr}}{\text{ molar mass of Cr}}= \frac{68.4g}{52g/mole}=1.31moles[/tex]
Moles of O =[tex]\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{31.5g}{16g/mole}=1.97moles[/tex]
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For Cr = [tex]\frac{1.31}{1.31}=1[/tex]
For O = [tex]\frac{1.97}{1.31}=1.5[/tex]
The simple whole number ratio of Cr : O= 2: 3
Hence the empirical formula is [tex]Cr_2O_3[/tex]
