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2014-03-25T20:55:28+02:00
A)Na2CO3 => masa molara = 2*23+12+48=106 g/mol
%Na = masa sodiu/masa carbonat * 100 = 2 * 23/106 * 100
%C = masa carbon/masa carbonat * 100 = 12/106 * 100
%O = masa oxigen/masa carbonat * 100 = 3 * 16/106 * 100
b)CCl4 => masa molara = 12 + 4*35,5 =144g/mol
%C = 12/144 * 100
%O = 4 * 35,5/144 * 100
c)H2CO3 => masa molara = 2+12+48=62 g/mol
%H = 2/62 * 100
%O = 3 * 16/62 * 100
%C = 12/62 * 100

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