10.10 2Pb(NO3)2 ⇒ 2PbO + 4NO2 + O2
N⁵⁺ + 1e ⇒ N⁴⁺ se reduce Pb(NO3)2 = agent oxidant
O²⁻ ⇒ 1/2 O2 + 2e se oxideaza Pb(NO3)2 = agent reducator (autooxidoreducere)
b) 6,022·10²⁴ e⁻ ⇔ 10moli e⁻ ⇒ 20 moli Pb(NO3)2 ⇒ 20 moli PbO
m = 20·223 = 4460 g
c) nPb(NO3)2 pur = 20·100/ 80 = 25moli m = 25·331 = 8275g
m imp. = 8275·100/ 90 = 9194,44g
10.11 4HNO3 +3 S ⇒3 SO2 +4 NO + 2H2O
NxOy 14x·100/(14x +16y) = 46,66 30x = 14x + 16y 16x = 116y x = y
oxidul : NO
N⁵⁺ + 3e⁻ = N²⁺ se reduce HNO3 = agent oxidant
S⁰ = S⁴⁺ + 4e⁻ se oxideaza S = agent reducator
5HNO3 +3 P + 2H2O =3 H3PO4 + 5NO
N⁵⁺ + 3e⁻ = N²⁺ se reduce HNO3 = agent oxidant
P⁰ = P⁵⁺ + 5e⁻ se oxideaza P = agent reducator
b) in HNO3 NO N = maxim (+5) ⇒⇒ el nu se mai poate oxida (nu poate fi agent reducator)
c) n e⁻ =3, 6132·10^23 ⇔⇔ n e = 1,(6) = 5/3 moli electroni ⇒⇒
⇒⇒ nS = 5/3 ÷4 = 5/12 moli
n gaze = 5/12 + 4/3·5/12 = 7/3 ·5/12 = 35/36 moli V = 35/36 ·22,4 = 21,77 l
d) n NO = 4/3·5/12 = 5/9 moli
nP = 3/5 ·nNO = 3/5·5/9 = 1/3 moli m = 1/3×31 = 10,33g
