Answer: 1 mole of [tex]Ca[/tex] has the greatest mass.
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP , contains avogadro's number [tex](6.023\times 10^{23})[/tex] of particles and weighs equal to the molecular mass of the substance.
1 mole of [tex]Ca[/tex] has a mass of 40 g.
1 mole of [tex]CO[/tex] has a mass of 28 g
1 mole of [tex]O_2[/tex] has a mass of 32 g
1 mole of [tex]CH_4[/tex] has a mass of 16 g.
1 mole of [tex]NO[/tex] has a mass of 30 g.
Thus the greatest mass is of 1 mole of [tex]Ca[/tex]
