Help with Avogadro's Law problem?

Question

A 20.0-L stainless steel container was charged with 2.38 atm of hydrogen gas and 3.00 atm oxygen gas. A spark ignited the mixture, producing water. What is the pressure in the tank at 25 ºC? at 125 ºC

--My teacher said it has something to do with Avogadro's Law, but I have no idea how to even set up the problem since volume is constant??

Hints:
pt 1-- Since V and T are constant, Avogadro’s Law applies. Hydrogen is the limiting reactant.
pt 2--At this temperature the water is also a gas, and its pressure should be added to the pressure of remaining oxygen.

I think it does have to do with partial pressure, but then I'm not sure how the temperature would tie in

Answer 1

Teacher has got it right. The reaction of interest is 2H2 +O2 -> 2 H2O. Since the partial pressures are in the same ratio as the moles present, 2.38 atm of H2 will react totally with 1.19 atm of O2. So if all the hydrogen is consumed and the pressure of water vapor can be neglected at 25 deg C, and the volume of liquid water neglected, You would have 3-1.19 atm left in the chamber.

At 125 deg C, all the water has vaporized. Since it has the same number of moles of the initial H charge, the pressure can be computed fromthe pressure of the original components (supposedly at 25 deg C) as (125+273.2) [5.38 atm]/(25+273.20

Answer 2

Does it have something to do with Dalton's law of partial pressures?

Pressure of H + Pressure of O = Total Pressure

Answer 3

without expertise gravity all the regulations are futile thats why technology is in the back of and backwards in u.s....and excelling someplace else...newton...and einstein have been the two incorrect...there theorys have been unsuitable.....all the technology we've discovered has been off through omit caculations thats why technology has paused with the purpose to communicate...think of out the field