Question

Perchloroethylene, also known as perc, is the solvent used in most dry cleaning. It consists of C and Cl. Determine the empirical formula of perchloroethylene given that a 2.58−g sample yields 1.37 g CO2 in a combustion analysis experiment

Answer 1

CCl₂

Step-by-step explanation:

Let us calculate the mass of carbon present in 100 grams of sample.

The formula to calculate the mass of carbon we can use the following formula.

`(12XmassofcarbondioxideX100)/(44Xmassofsample)=(12X1.37X100)/(2.58x44)=14.5`

The mass of chlorine in the sample = 100-14.5 = 85.5g

Let us calculate the moles of each element:

moles of carbon =
`(mass)/(atomicmass)=(14.5)/(12)=1.208`

Moles of chlorine =
`(mass)/(atomicmass)=(85.5)/(35.5)=2.41`

The mole ratio is :

C:Cl = 1.208:2.41 = 1:2

So the empirical formula of the compound must be CCl₂