Respuesta :
Answer : The molecular formula of a compound is, [tex]C_8H_8O_2[/tex]
Solution :
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 C = 70.6 g
Mass of H = 5.9 g
Mass of O = 23.5 g
Molar mass of C = 12 g/mole
Molar mass of H = 1 g/mole
Molar mass of O = 16 g/mole
Step 1 : convert given masses into moles.
Moles of C = [tex]\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{70.6g}{12g/mole}=5.88moles[/tex]
Moles of H = [tex]\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{5.9g}{1g/mole}=5.9moles[/tex]
Moles of O = [tex]\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{23.5g}{16g/mole}=1.47moles[/tex]
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For C = [tex]\frac{5.88}{1.47}=4[/tex]
For H = [tex]\frac{5.9}{1.47}=4.01\approx 4[/tex]
For Cl = [tex]\frac{1.47}{1.47}=1[/tex]
The ratio of C : H : O = 4 : 4 : 1
The mole ratio of the element is represented by subscripts in empirical formula.
The Empirical formula = [tex]C_4H_4O_1=C_4H_4O[/tex]
The empirical formula weight = 4(12) + 4(1) + 1(16) = 68 gram/eq
Now we have to calculate the molecular formula of the compound.
Formula used :
[tex]n=\frac{\text{Molecular formula}}{\text{Empirical formula weight}}[/tex]
[tex]n=\frac{136}{68}=2[/tex]
Molecular formula = [tex](C_4H_4O)_n=(C_4H_4O)_2=C_8H_8O_2[/tex]
Therefore, the molecular of the compound is, [tex]C_8H_8O_2[/tex]
