Question The relative molecular mass of the oxalic acid is 90 and its composition by mass is Carbon = 26.7% Hydrogen = 2.2% Oxygen = 71.1%
Calculate the empirical and molecular formula?

Explanation:

Assume 100 g of acid. Breaking it down into its components, there are

26.68

⋅

g

12.01

⋅

g

⋅

m

o

l

−

1

⋅

C

;

2.24

⋅

g

1.00794

⋅

g

⋅

m

o

l

−

1

⋅

H

;

71.08

⋅

g

16.00

⋅

g

⋅

m

o

l

−

1

⋅

O

=

C

:

H

:

O

=

2.22

:

2.22

:

4.44

=

1

:

1

:

2

.

Therefore, empirical formula of oxalic acid is

C

H

O

2

. If its molecular mass is

90.03

⋅

g

⋅

m

o

l

−

1

, what is its molecular formula?