Discussão:Metal alcalino

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The sentence "2 Li (s) + 2 H2O (l) → 2 LiOH (aq) + H2 ↑" describes an irreversible process, that is:

2 Li (s) + 2 H2O (l) → 2 LiOH (aq) + H2  2 Li (s) + 2 H2O (l) → 2 LiOH (aq) + H2 (g)  ( 2 LiOH (aq) + H2 (g) → 2 Li (s) + 2 H2O (l) )
N.B.
The sentence "NaCl (aq) + AgNO3 (aq) → NaNO3 (aq) + AgCl ↓" is another example of the sentences that describe the irreversible chemical processes.
NaCl (aq) + AgNO3 (aq) → NaNO3 (aq) + AgCl ↓   NaCl (aq) + AgNO3 (aq) → NaNO3 (aq) + AgCl (s)  ( NaNO3 (aq) + AgCl (s) → NaCl (aq) + AgNO3 (aq) )


The sentence "2 Li (s) + 2 H2O (l) → 2 LiOH (aq) + H2 ↑" describes a redox process, that is:

2 Li (s) + 2 H2O (l) → 2 LiOH (aq) + H2  2 Li0 (s) + 2 H+12O (l) → 2 Li+1OH (aq) + H02 (g)


The sentence "2 Li (s) + 2 H2O (l) → 2 LiOH (aq) + H2 (g)" may be inferred from the following sentences:

Li (s) → Li+(aq) + e
2 H+(aq) + 2 e → H2 (g)
H2O (l) = H+(aq) + OH(aq)
LiOH (aq) = Li+(aq) + OH(aq)


Inference
  Li (s) → Li+(aq) + e   2 H+(aq) + 2 e → H2 (g)   H2O (l) = H+(aq) + OH(aq)   LiOH (aq) = Li+(aq) + OH(aq)  


2 Li (s) → 2 Li+(aq) + 2 e   2 H+(aq) + 2 e → H2 (g)   H2O (l) = H+(aq) + OH(aq)   LiOH (aq) = Li+(aq) + OH(aq)  


2 Li (s) + 2 H+(aq) + 2 e → 2 Li+(aq) + 2 e + H2 (g)   2 H2O (l) = 2 H+(aq) + 2 OH(aq)   2 LiOH (aq) = 2 Li+(aq) + 2 OH(aq)  


2 Li (s) + 2 H+(aq) → 2 Li+(aq) + H2 (g)   2 H+(aq) = 2 H2O (l) − 2 OH(aq)   2 Li+(aq) = 2 LiOH (aq) − 2 OH(aq)  


2 Li (s) + 2 H2O (l) − 2 OH(aq) → 2 LiOH (aq) − 2 OH(aq) + H2 (g)  


2 Li (s) + 2 H2O (l) → 2 LiOH (aq) + H2 (g)  


The sentence "2 Li (s) + 2 H2O (l) → 2 LiOH (aq) + H2 ↑" may be inferred from the following sentences:

Li (s) → Li+(aq) + e & Eox = −3.045 V
2 H+(aq) + 2 e → H2 (g) & Ered = 0 V
H2O (l) = H+(aq) + OH(aq)
LiOH (aq) = Li+(aq) + OH(aq)


Inference
  Li (s) → Li+(aq) + e& Eox = −3.045 V   2 H+(aq) + 2 e → H2 (g) & Ered = 0 V   H2O (l) = H+(aq) + OH(aq)   LiOH (aq) = Li+(aq) +
+ OH(aq)  


2 Li (s) + 2 H+(aq) + 2 e → 2 Li+(aq) + 2 e + H2 (g) & Eredox = Ered − Eox = (0 − −3.045) V = +3.045 V   2 H2O (l) = 2 H+(aq) + 2 OH(aq)
  2 LiOH (aq) = 2 Li+(aq) + 2 OH(aq)  


2 Li (s) + 2 H+(aq) → 2 Li+(aq) + H2 (g) & Eredox = 3.045 V   2 H+(aq) = 2 H2O (l) − 2 OH(aq)   2 Li+(aq) = 2 LiOH (aq) − 2 OH(aq)  


2 Li (s) + 2 H2O (l) → 2 LiOH (aq) + H2 (g) & Eredox > 0 V  


2 Li (s) + 2 H2O (l) → 2 LiOH (aq) + H2 


The sentence "2 Li (s) + 2 H2O (l)T = 298.15 K 2 LiOH (aq) + H2 (g) & Eredox = 3.045 V" contains the adverbial clause "T = 298.15 K" and may be inferred from the following sentences:

T = 298.15 K   Li (s) → Li+(aq) + e & Eox = −3.045 V
T = 298.15 K   2 H+(aq) + 2 e → H2 (g) & Ered = 0 V
T = 298.15 K   H2O (l) = H+(aq) + OH
T = 298.15 K   LiOH (aq) = Li+(aq) + OH(aq)


Inference
  ( T = 298.15 K   Li (s) → Li+(aq) + e & Eox = −3.045 V )   ( T = 298.15 K   2 H+(aq) + 2 e → H2 (g) & Ered = 0 V )
  ( T = 298.15 K   H2O (l) = H+(aq) + OH(aq) )   ( T = 298.15 K   LiOH (aq) = Li+(aq) + OH(aq) )  


T = 298.15 K   ( Li (s) → Li+(aq) + e & Eox = −3.045 V   2 H+(aq) + 2 e → H2 (g) & Ered = 0 V   H2O (l) = H+(aq) + OH(aq)
  LiOH (aq) = Li+(aq) + OH(aq) )  


T = 298.15 K   2 Li (s) + 2 H2O (l) → 2 LiOH (aq) + H2 (g) & Eredox = 3.045 V  


2 Li (s) + 2 H2O (l)T = 298.15 K 2 LiOH (aq) + H2 (g) & Eredox = 3.045 V  
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