#M_(CO_2) = "220 mg"#
#MW_(CO_2) = "44.01 g/mol"#
#"O"_2 " molecules = ?"#
#"moles " CO_2 = (M_(CO_2))/(MW_(CO_2)) = ("220 mg"/"1000 mg/g")/"44.01 g/mol" = "0.00500 mol"#
#"moles O"_2 " per mole CO"_2 = 1#
#"Avogadro's number" = N_A = 6.022 xx 10^23" molecules/mol"#
#"O"_2 " molecules" = "moles CO"_2 xx "moles O"_2 /"moles CO"_2 xx N_A#
# = "0.00500 mol CO"_2 xx ("1 mol O"_2)/("1 mol CO"_2) xx (6.022 xx10^23 " molecules O"_2)/("1 mol O"_2)#
# = 3.01 xx 10^21" molecules O"_2#
