Question

The mass of 94.5 ml of gas at STP is found to be 0.2231g. Calculate its molecular mass

• A. 52.88 u
• B. 26.44 u
• C. 104 u
• D. 102.88 u

Answer 1

The correct option is A 52.88 u

$n=\frac{W}{M}=\frac{N}{N_A}=\frac{V}{22.4}\left(L\right)$
$=\frac{V}{22400}\left(mL\right)$
$\frac{W}{M}=\frac{V}{22400}$
$\frac{0.2231}{M}=\frac{94.5}{22400}$
$M=\frac{0.2231\times 22400}{94.5}$
= 52.88 u