Respuesta :
Answer: The molecular formula will be [tex]C_8H_8O_2[/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 C= 70.6 g
Mass of H = 5.9 g
Mass of O = 23.5 g
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}=5.9moles[/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}=1.5moles[/tex]
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For C = [tex]\frac{5.9}{1.5}=4[/tex]
For H = [tex]\frac{5.9}{1.5}=4[/tex]
For O =[tex]\frac{1.5}{1.5}=1[/tex]
The ratio of C : H: O= 4: 4:1
Hence the empirical formula is [tex]C_4H_4O[/tex]
The empirical weight of [tex]C_4H_4O[/tex] = 4(12)+4(1)+1(16)= 68g.
The molecular weight = 136 g/mole
Now we have to calculate the molecular formula.
[tex]n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}=\frac{136}{68}=2[/tex]
The molecular formula will be=[tex]2\times C_4H_4O=C_8H_8O_2[/tex]
