[samiam991]

Hi I need help understanding this solution.
10g H2 and 54 g of o2 are contained in a 10 L flask at 200 degrees Celsius.
Upon sparking what is the final pressure of the container.
a equation
2H2 + 02  -->2H20
5 mol   2 mol
we know H20 is in vapor form.
solution shows  H2 is excess, O2 is limiting reagent.

I am confused as to why 4 mol of H20 and 1 mol of H2 is used to calculate pressure
P=n(total)RT/V

thanks!

[fledarmus]

If all of your oxygen reacts with as much hydrogen as it can, how much hydrogen is left over? How much water is formed? How much oxygen is left over?

[Borek]

I am confused as to why 4 mol of H20 and 1 mol of H2 is used to calculate pressure

Where did you get these numbers from? They are incorrect.

[fledarmus]

I am confused as to why 4 mol of H20 and 1 mol of H2 is used to calculate pressure

Where did you get these numbers from? They are incorrect.

Oops - based on the original post, I just assumed "54 g of O2" was a typo and should have read "64 g of O2" - samiam991, was that the case?

[samiam991]

Yep you are correct it was a typo on my part.
And I understand that this was a question based on ratio.
because oxygen to water is 1:2
2 mol of oxygen used up means 4 mols of h20 are produced.
and the ratio of h2 to o2 is 2:1
so 4 mols of H2 is used up for 2 mols of oxygen used,leaving 1 mol of H2 left.

I am confused as to why 4 mol of H20 and 1 mol of H2 is used to calculate pressure

Where did you get these numbers from? They are incorrect.

Oops - based on the original post, I just assumed "54 g of O2" was a typo and should have read "64 g of O2" - samiam991, was that the case?