further inquiry to the NIST database reveals the real issue, entropy .
ΔS for the Li reaction is 117.84 J/mol-K, ΔH being 117.65 kJ/mol yields spontaneous reaction at ~ 1000K
ΔS for the Mg reaction is 241.77 J/mol-K, ΔH being 414.21 kJ/mol yields spontaneous reaction at 1717K, much above the 1000C OP mentioned.
Funnily enough this temperature criteria can be seen in codys video when he did the Na reaction (for which the reaction is spontaneous above 1108K):
https://youtu.be/PkTaz3UEThY?t=176
He didnt get any product at 1400F (1033K), but as soon as he changed to 1550F (1116K) he got the potassium. He also failed the Mg reaction with 1600F
(1144K)
[Edited on 5-8-2023 by RustyShackleford] |