NaNO3 - azotat de potasiu
masa molara = 23+14+3*16=85 g/mol
%N = masa azot/masa molara azotat * 100 = 14/85*100 = 16,471%
%O = masa oxigen/masa molara azotat * 100 = 3*16/85*100 = 56,471%
%Na = masa sodiu/masa molara azotat * 100 = 23/85*100 = 27,059%
raport de masa Na:N:O = 23:14:3*16=23:14:48