It can be oxygen in only 1 atom. All elements on the periodic table can stand alone in one atom.
(I took a lucky guess, using some of my knowledge about elements )
it is called the partial pressure because it is pressure that is exerted by each gas in a mixture of gases if it occupy the same volume of it own. the the partial pressure of oxygen in the air sample above is 100 mm hg, that of carbon dioxide is 40 mmhg, for water vapor 47 mmhg. and that of nitrogen is 573 mmhg
The answer is C. 146g because you add all of the masses of the individual elements and then mulyiply by 1.72 to get your answer.
