Question #1571e

1 Answer
Nov 7, 2017

Because atoms are small and we can't see them, and because phosphorus naturally exists as a tetratomic molecule.


In #"1 mol"#, the phosphorus atoms #"P"# have a mass of #"30.97 g"#. Therefore,

#m_P = "30.97 g"/cancel"1 mol P" xx (cancel"1 mol anything ever")/(6.022 xx 10^23 "anything ever")#

#= 5.143 xx 10^(-23) "g"#

But phosphorus exists as #"P"_4(s)#, so

#color(blue)(m_(P_4)) = 4 cdot m_(P)#

#= 4 cdot 5.143 xx 10^(-23) "g"#

#= color(blue)(2.057 xx 10^(-22) "g")#