Answer :
Answer: The empirical formula of compound is [tex]C_4H_{12}Si[/tex].
Explanation:
Mass of Sample= 0.702 g
Mass of [tex]CO_2[/tex] = 1.4 g
Mass of [tex]H_2O[/tex] = 0.86 g
Mass of [tex]SiO_2[/tex] = 0.478 g
First we have to calculate moles of[tex]CO_2[/tex], [tex]H_2O[/tex] and [tex]SiO_2[/tex] formed.
1. Moles of [tex]CO_2=\frac{1.4g}{44g/mol}=0.032mol[/tex]
Now , Moles of carbon == Moles of [tex]CO_2[/tex] = 0.032
2. Moles of [tex]H_2O=\frac{0.86g}{18g/mol}[/tex]=0.048mol
Now , Moles of hydrogen = [tex]2\times[/tex] Moles of [tex]H_2O[/tex] =[tex]2\times 0.048=0.096mol[/tex]
3. Moles of [tex]SiO_2=\frac{0.478g}{60g/mol}=0.008[/tex] mol
Now , Moles of silicon = Moles of [tex]SiO_2[/tex] = 0.008 moles
Therefore, the ratio of number of moles of C : H : Si is = 0.032 : 0.096 : 0.008
For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For C= [tex]\frac{0.032}{0.008}=4[/tex]
For H =[tex]\frac{0.096}{0.008}=12[/tex]
For Si=[tex]\frac{0.008}{0.008}=1[/tex]
Thus, C: H: Si = 4 : 12 : 1
The simplest ratio represent empirical formula.
Hence, the empirical formula of compound is [tex]C_4H_{12}Si[/tex].