Q. A carbon compound containing carbon and oxygen has approximate molar mass equal to $290$ . On analysis it is found to contain $50 \%$ by mass of each element. Therefore, molecular formula of the compound is:
Some Basic Concepts of Chemistry
Solution:
Element
C
O
$\% $by mass
50
50
Ratio by no. of atoms:
50
50
12
16
Simplest ratio by no of atoms : $4: 3$
$\therefore $ Empirical formula $= C _{4} O _{3}$
And let molecular formula be $\left( C _{4} O _{3}\right)_{n}$
$\therefore 96 n=290$
or $n=\frac{290}{96} \simeq 3$
$\therefore $ Molecular formula is $C _{12} O _{9}$
| Element | C | O |
|---|---|---|
| $\% $by mass | 50 | 50 |
| Ratio by no. of atoms: | 50 | 50 |
| 12 | 16 |