Question

Cortisone is a molecular substance substance containing `21` atoms of carbon per molecule. The mas percentage of carbon in cortisone is `69.98%`. Its molar mass is :
A. `176.5`
B. `252.2`
C. `287.6`
D. `360.1`

Answer 1

Correct Answer - D
In cortisone
69.98 g C =- 100 g cortisone
1 mole of cortisone contain 21 moles of carbon atoms or 252 g of carbon
252 g carbon = 1 mol cortisone
69.98 g carbon `= (69.98)/(252)` mol cortisone
`(69.98)/(252)` mol cortisone = 100 g
1 mol cortisone `= (100gxx252)/(69.98) = 360.10g`
`:.` Molar mass of cortisone `= 360.10g mol^(-1)`