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Heat of Reaction of Alkali metal with water.
2

Heat of Reaction of Alkali metal with water.

Heat of Reaction of Alkali metal with water.

(OP)
Please, can someone help me out with the actual values of the Heat of Reaction of Potassium + Water, and Calcium Hydride + Water?

Thanks in advance.

RE: Heat of Reaction of Alkali metal with water.

2
This is similar to the prior case for NaH.
Data are from Perry’s, 7th ed., Table 2-220.

For potassium + water, the stoichiometric reaction (no excess water) is

    K(s) + H2O(l) --> KOH(s) + ½ H2(g)

ΔHRxn, 25 C = -102.02 + 0 – 0 – (-68.32) = -33.7 kcal/mol

For potassium + water, with excess water (value is for final solution KOH in 400 H2O), the reaction is

    K(s) + H2O(l) --> KOH(aq, 400H2O) + ½ H2(g)

ΔHRxn, 25 C = -114.96 + 0 – 0 – (-68.32) = -46.64 kcal/mol

For CaH2, the stoichiometric reaction (no excess water) is

    CaH2(s) + 2 H2O(l) --> Ca(OH)2(s) + 2 H2(g)

ΔHRxn, 25 C = - 235.58 + 0 – (-46) – 2(-68.32) = -52.94 kcal/mol

For CaH2, the reaction with excess water is

    CaH2(s) + 2 H2O(l) --> Ca(OH)2(aq, 800H2O) + 2 H2(g)

ΔHRxn, 25 C = - 239.2 + 0 – (-46) – 2(-68.32) = -56.56 kcal/mol

These reactions may be vigorous, and possibly explosive without excess water.  Lots of heat (even more if the H2 ignites!).  What is your application?

RE: Heat of Reaction of Alkali metal with water.

(OP)
kenvlach, the application is confidential, but I can tell you that I wish to generate an enormous amount of heat, albeit via as cheap a reaction as possible. Thank you for your reply, as it further helps me in my investigation. Any ideas you may have along these lines would be equally helpful. You have my vote...

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