10)
H2O
%O = 16/18 * 100 = 88.888%
H2SO4
%O = 4*16/98 * 100 = 65.306%
HNO3
%O = 3*16/63 * 100 = 76.190%
(NH4)2CO3
%O = 3*16/96 * 100 = 50%
11)
MeCl2
%Cl = m Cl/m MeCl2 * 100
74.73 = 2*35.5/m MeCl2 * 100
m MeCl2 = 95 g
x + 2*35.5 = 94 => x = 24 => Mg => MgCl2
12)
Me(NO3)2
%O = m O/m Me(NO3)2 * 100
58.53 = 2*3*16/m Me(NO3)2 * 100
m Me(NO3)2 = 164 g
x + 2*(14+3*16) = 164 => x = 40 => Ca => Ca)NO3)2
13)
3.06/1 = 3.06
31.63/31 = 1.02
65.30/16 = 4.08
Imparti la 1.02 => H3PO4
