Question

A compund containing carbon, hydrogen and oxygen gave the following data : C= 40.0% and H= 6.67% . Calculate the molecular formula of the compound if its vapour density is 90.

Answer 1

Solution:-Vapour density=

$\frac{molar \: mass}{2 } = vapour \: density \\ molar \: mass = 2 \times vapour \: density \\ molar \: mass = 180$

molar mass =molecular mass of compound...

Let the total mass of the compound be 100g

mass of carbon in it =40g

mass of hydrogen in it=6.67g

mass of oxygen=100-46.67=53.33g

moles of carbon=40/12=3.3moles

moles of hydrogen=6.6/1=6.6moles

mass of oxygen=53.33/16=3.3moles

ratio of their moles=3.3:6.6:3.3=1:2:1

so,

it's empirical formula=CH2O

empirical mass=12+2+16=30

n=molecular mass/empirical mass

=180/30=6

molecular formula=6×empirical formula=6×CH2O

=C6H12O6

Hence this will be required formula

{hope it helps you}

Answer 2

Answer:

see the attachment ✌️❣️