QUESTION: If I have say 1 oz. of H2O and put it in a 150 oz. strong box. heat it up to 500 degrees Fahrenheit how many psia. will there be
ANSWER: You have not added any volume, there fore there is no noticeable increase in pressure, other than the expansion of air.
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QUESTION: Let me rephrase. So 1 oz. of H2O(water) at say 70 degrees Fahrenheit.Put it in a 150 oz. strong box (sealed container) at atmospheric pressure. Now heat it up to 500 degrees Fahrenheit. What will the steam pressure be in psi. or bar. in the container/strong box?
Ok, now I understand a bit better, You are attempting to separate the Hydrogen from Oxygen. The hydrogen will expand considerably above the boiling/separation point. If you start with a vacuum, Not expanding the existing air in this chamber, it would be far greater pressures. Expanding the H2O into conformed atmosphere, may be explosive. the only way I would know how to measure,,,,controled conditions and a pressure gauge on the tank/box. Heat the box without H20 for comparison, then add water and reheat to controled 500