Question

Nox dos elementos na especie:
A) K3PO4
B) Al2(CO3)3
D) NO3^1-
E) Pb(OH)2^2+

Answer 1

 +1  -2
$k_{3}PO_{4}$
3 x 1 + P + 4 (-2) =0
3 + P - 8 = 0
P = 5
K: 1
O: -2

$Al_{2}(CO_{3})_{3}$
2 x 3 + 3C + 3 x3 x (-2) = 0
6 + 3C - 18 = O
3C = 12
C = 12/3
C = 4
Al: +3
O: -2

$NO_{3}^{-1}$
N + 3 (-2) = -1
N = 6 - 1
N = 5
O: -2

$Pb(OH) _{2} ^{-2}$
Pb + 2 (-2) + 2 .1 = +2
Pb - 4 + 2 = 2
Pb = 4 - 2 + 2
Pb = 4
O: -2
H: +1