How many units of hydrogen element are present in 11.2 litres of water vapour at NTP? step-by-step please!​

Which statement is best described as a atom

Silver tarnishes as silver metal reacts with hydrogen sulfide, h2s, in the air. in this reaction, dark silver sulfide, au2s, covers the surface of silver. when silver is polished, this coating of silver sulfide can be removed from the surface. this makes the silver shiny again. enter the coefficients that balance the tarnishing reaction equation. (type 1 for no coefficient.)

What is the percentage of hydrogen in nitrogen trihydride