Question

Aspirin is used as a mild pain killer. There are nine carbon atoms, eight hydrogen atoms and four oxygen atoms, in this compound. Write its empirical and molecular formulas.
please solve with formula

Answer 1

Answer:

Molar mass of C

9

H

8

O

4

=9×12+8×1+4×16

=180 gram/mole

180 gram C

9

H

8

O

4

≡108 gram carbon

∴x gram C

9

H

8

O

4

≡0.968 gram carbon

∴x=

108

0.968×180

=1.613 gram C

9

H

8

O

4

Now

180 gram C

9

H

8

O

4

≡8 gram Hydrogen

∴1.613 gram C

9

H

8

O

4

≡

180

8×1.613

=0.0717 gram 'H'

Option (b) correct.

Answer 2

Aspirin is used as a mild pain killer. There are nine carbon atoms, eight hydrogen atoms and four oxygen atoms, in this compound.

• Empirical Formula: Lowest whole number ratio of the elements in a compound

• Molecular Formula: Actual whole number ratio of the elements in a compound.

• Aspirin is made of H, O & C, and was analyzed to contain 60.0% carbon and 35.5% Oxygen.

• Molar mass of $C_{9} H_{8} O_{4}$  =9×12+8×1+4×16

                                        =180 gram/mole

180 gram  $C_{9} H_{8} O_{4}$ = 108 gram carbon

∴x gram  = 0.968 gram carbon

∴x = (0.968×180)/108

    = 1.613 gram $C_{9} H_{8} O_{4}$

​

Now , 180 gram $C_{9} H_{8} O_{4}$ = 8 gram Hydrogen

∴1.613 gram $C_{9} H_{8} O_{4}$ = (8×1.613)/180

                                   =0.0717 gram 'H'

The above equations derives the empirical and molecular formulas of aspirin.

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