A sample of 29.344 g of dinitrogen monoxide reacts with an excess of oxygen to form 61.343 g of dinitrogen tetroxide. According to the Law of Conservation of Mass, the amount of oxygen gas that reacted with the nitrogen-containing gas is: 90.687 g O, 2

47.997 g O2
47.997 g O, 2

31.999 g O, 2

2.090 g O, 2

the grams   of   barium that   are in   2.3 x 10^23   atoms of barium   is   52.4 g (answer c)

    calculation

mass = moles   of ba   x molar   mass of ba

  molar mass of ba from periodic table=   137.3 g/mol

  use the   avogadro's law   constant   to   calculate the moles of barium

  that   is     1 mole =   6.02   x 10^23 atoms

                    ? moles = 2.3 x 10^23   atoms

by cross   multiplication

=(1 mole   x 2.3x 10^23 atoms)   / 6.02   x10^23 atoms)=   0.382   moles

mass   is therefore = 137.3   g/mol x 0.382 mol = 52.4 ( answer c)

explanation: