Respuesta :
Answer: The empirical formula is [tex]CH_2[/tex] and molecular formula is [tex]C_4H_8[/tex]
Explanation:
We are given:
Mass of [tex]CO_2[/tex] = 18.95 g
Mass of [tex]H_2O[/tex]= 7.759 g
Molar mass of carbon dioxide = 44 g/mol
Molar mass of water = 18 g/mol
For calculating the mass of carbon:
In 44g of carbon dioxide, 12 g of carbon is contained.
So, in 18.59 g of carbon dioxide, =[tex]\frac{12}{44}\times 18.59=5.07g[/tex] of carbon will be contained.
For calculating the mass of hydrogen:
In 18g of water, 2 g of hydrogen is contained.
So, in 7.759 g of water, =[tex]\frac{2}{18}\times 7.759=0.862g[/tex] of hydrogen will be contained.
Mass of C = 5.07 g
Mass of H = 0.862 g
Step 1 : convert given masses into moles.
Moles of C =[tex] \frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{5.07g}{12g/mole}=0.422moles[/tex]
Moles of H=[tex]\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{0.862g}{1g/mole}=0.862moles[/tex]
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For C =[tex]\frac{0.422}{0.422}=1[/tex]
For H =[tex]\frac{0.862}{0.422}=2[/tex]
The ratio of C : H = 1: 2
Hence the empirical formula is [tex]CH_2[/tex].
The empirical weight of [tex]CH_2[/tex] = 1(12)+2(1)= 14 g.
The molecular weight = 56.1 g/mole
Now we have to calculate the molecular formula.
[tex]n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}=\frac{56.1}{14}=4[/tex]
The molecular formula will be=[tex]4\times CH_2=C_4H_8[/tex]
