Question

How can I find the percent compositions of Mg(NO3)2?

Answer 1

To find percent composition we need to begin by finding the gram formula mass of the `Mg(NO_3)_2` compound.

Mg 1 atom x 24.31 = 24.31
N 2 atoms x 14.01 = 28.02
O 6 atoms x 15.99 = 95.94
Total Mass = 148.27 g/mol

% Magnesium = `(24.31/148.27)`= .164 or 16.4 %
% Nitrogen = `(28.02/148.27)` = .189 or 18.9%
% Oxygen = `(95.94/148.27)` = .647 or 64.7%

I hope this was beneficial.
SMARTERTEACHER