Which of the following gases will effuse out of the football bladder most quickly?
(1) He
(2) H2
(3) N2
(4) O2
Answer: (2) Hydrogen is a chemical element with the symbol H and atomic number 1. With an average atomic weight of 1.00794 u (1.007825 u for hydrogen-1), hydrogen is the lightest element, and its monatomic form (H1) is the most abundant chemical substance, constituting roughly 75% of the Universe’s baryonic mass. Naturally occurring atomic hydrogen is rare on Earth because hydrogen readily forms covalent compounds with most elements and is present in the water molecule and in most organic compounds.
