# Chemistry - Gas Laws Problem 1

A 20 liter stainless steel container was charged with 2 atm of hydrogen gas and 3 atm of oxygen gas. A spark ignited the mixture, producing water. What is the pressere in the tank at 25 degrees C?

If the reaction in the above problem occurred at 125 degrees C, what would the pressure in the tank be?

I know that this problem has to do with Dalton's Law of Partial Pressures and since water is involved, the pressure of water vapor will have to be factored in. But other than that, this problem is much more complex than what we have been doing and I would appreciate some help with it. Thanks.

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Bystander
Homework Helper
Gold Member
1. xs O2 pressure is 2 atm, assuming absolute pressure and 25 C.
2. ~ 2 mol H2O formed at 25 C in 20 liters,
3. is 2.03 atm. (2.00 + 25/760, strictly + Poynting correction to water vapor pressure, negligible under xs O2 pressure).
4. At 125 C, PH2O > 2 atm, totally evaporated, and PTotal = PO2(125 C) + PDry/Superheated.

Chestermiller
Mentor
A 20 liter stainless steel container was charged with 2 atm of hydrogen gas and 3 atm of oxygen gas. A spark ignited the mixture, producing water. What is the pressere in the tank at 25 degrees C?

If the reaction in the above problem occurred at 125 degrees C, what would the pressure in the tank be?

I know that this problem has to do with Dalton's Law of Partial Pressures and since water is involved, the pressure of water vapor will have to be factored in. But other than that, this problem is much more complex than what we have been doing and I would appreciate some help with it. Thanks.
In the initial state, if you have 20 liters of gas at 5 atm and 25 C, what is the total number of moles of gas that you have? From this, how many moles of oxygen do you have and how many moles of hydrogen do you have? What is the balanced chemical equation for the reaction of oxygen and hydrogen?