# Relative volume of combusted hydrogen

bobbyg
Hi,

If I had a volume of Brown's gas at 20°C / 1atm, what would the expected volume [of the resultant steam] be immediately after it was ignited?

Thanks!
Bob

DrStupid
If I had a volume of Brown's gas at 20°C / 1atm, what would the expected volume [of the resultant steam] be immediately after it was ignited?

In a sufficiently strong container it would remain unchanged. Please specify the conditions.

bobbyg
In a sufficiently strong container it would remain unchanged. Please specify the conditions.
The container is solid, with a freely-moving piston of negligible mass

Homework Helper
The container is solid, with a freely-moving piston of negligible mass
You will want to nail the scenario down more tightly than that.

For instance, do you want the steam to more or less freely (and adiabatically) expand until it has reached ambient pressure? This, while doing work on the piston against the force of ambient pressure on its other side?

Oh... and is this homework by any chance?

Mentor
How many moles of gas are there before combustion? How many moles of gas are they after combustion? Is the reaction assumed to take place at constant temperature, or is the system insulated?

bobbyg
Edit: don't worry. I will just try some physical experiments. Thanks for taking the time to reply

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DrStupid
Edit: don't worry. I will just try some physical experiments.

"Don't worry" and "just try some physical experiments" with Brown's gas don't fit together.

jrmichler
Gold Member
"Don't worry" also does not go well with combustion experiments performed by inexperienced students, especially if it is hydrogen. I am currently assisting with a combustion course and these kind of questions (e.g. computing volume expansion of a combustion process at constant pressure ) are covered in the second lecture.
My advice as a professional combustion researcher to you is: do not do combustion experiments.