$K_3PO_4$
$M_{K_3PO_4}$ $=$ $39.2 + 31 + 16.4 = 212 đvC $
%$ m_K$ $=$ $\frac{39.2}{212}$ $.100$% $=$ $55,19$%
%$ m_P$ $=$ $\frac{31}{212}$ $.100$% $=$ $14,62$%
%$ m_O$ $=$ $\frac{16.4}{212}$ $.100$% $=$ $30,19$%
$Ca(HCO_3)_2$
$M_{Ca(HCO_3)_2}$ $=$ $40 + 1.2 + 12.2 + 16.3.2 = 162 đvC $
%$m_{Ca}$ $=$ $\frac{40}{162}. 100$% $= 24,69$%
%$m_{H}$ $=$ $\frac{1.2}{162}.100$% $= 1,23$%
%$m_{C}$ $=$ $\frac{12.2}{162}.100$% $= 14,81$%
%$m_{O}$ $=$ $\frac{16.3.2}{162}.100$% $= 59,26$%
$FeCl_3$
$M_{FeCl_3}$ $=$ $56 + 35,5.3 = 162,5 đvC $
%$m_{Fe}$ $=$ $\frac{56}{162,5}.100$% $= 34,46$%
%$m_{Cl}$ $=$ $\frac{35,5.3}{162,5}.100$% $= 65,54$%
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