Question

The mass of 500 cc of hydrogen at S.T.P. is:

• A. 45 mg
• B. 90 mg
• C. 23.5 mg
• D. 4.5 mg

Answer 1

The correct option is A 45 mg

As we know,
One mole of each gas occupies $22.4litre$ volume at STP.

$2$ gram $H_2=22.4litre$

Here,
Volume of hydrogen = $500cc$

Mass of hydrogen $=500\times \frac{2}{22400}=45mg$

Hence, option $A$ is correct.