The answer is B. The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume.
Our only unknown is the volume<span> of H</span>2(g<span>) . Our known variables are P,n,R, and T. </span>At STP, the temperature is 273K and the pressure is 1 atm. Rearrange the equation to solve for V: n×R×TP. V=2.20mol<span> ×</span><span>0.0821L×atm mol×K ×273K 1atm. V=49.3L</span>
Explanation is in a file
bit.ly/3a8Nt8n