What is the number of nitrogen-based electrons in a #4.2*g# mass of nitride anion?

#A.# #0.30xxN_A;#
#B.# #30xxN_A;#
#C.# #3.0xxN_A;#
#D.# #4.2xxN_A;#
#E.# #"cannot be determined..."#

1 Answer
May 2, 2017

Answer:

Well, nitrogen has #Z=7#............

Explanation:

And if #Z=7#, and we have #N^(3-)#, we have 10 electrons per atom, i.e. #10*e^(-)xxN_A# electrons per mole of nitride anion.

But we have a mass of #4.2*g#, which corresponds to a molar quantity of #(4.2*g)/(14.01*g*mol^-1)=0.30*mol#.

And thus in a #0.30*mol# quantity of nitride anion, there are #10xx0.30*molxxN_A# quantity of electrons........ So we choose #"option c"#.

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