In: Chemistry
Now that Hermione understands empirical formulas she wants to teach Harry and Ron. What is the empirical formula for dibromoethane: C2H4Br2
A. CH2Br2
B. CH2Br
C. C2H4Br
D. CHBr
E. C2H2Br2
2.Calculate the maass percent composition of carbon in C2H5Cl.
(1) The empirical formula is the simplest formula for a compound.
Given molecular formula of dibromoethane is C2H4Br2
A molecular formula is the same as or a multiple of the empirical formula, and is based on the actual number of atoms of each type in the compound.
The ratio of C , H , Br in C2H4Br2 is C : H : Br = 2 : 4 : 2
The simplest ratio is C : H : Br = 1 : 2 : 1
So the emperical formula is CH2Br
(2) Given compound is C2H5Cl
Molar mass of C2H5Cl is = ( 2xAt.mass of C ) + (5xAt.mass of H ) + At.mass of Cl
= ( 2x12) + ( 5x1) + 35.5
= 64.5 g/mol
Molar mass of C is = 12 g/mol
So the mass percent of C = ( mass of C / Molar mass of C2H5Cl) x 100
= ( 12 / 64.5) x 100
= 18.6
Therefore the mass percent composition of carbon in C2H5Cl is 18.6 %