[awnashs]

Qu
Liquid Hydrogen is being used to power an experimental jet engine. In a particular test, in which all of the hydrogen fuel was oxidised, the fuel tank was found to have decreased in mass by 2.00 kg
What volume of oxygen, measured at standard temperature and pressure would be needed in this test run.

I first had trouble with the equation. What was the formula for liquid hydrogen?
I thought that the equation would be like
H2 + O2 react to equal 2H2O. or H2O2. But you dont really need the resultant formula.

I dont understand the question really. If it decreased by mass of 2.00 kg does that mean that it used 2.00 kg of Hydrogen? and in if that was the case then you would get (2000/2.016) = 992 moles of H2. which corresponds to 992 moles of O2.
I then used the formula (n=v/22.4) to get a volume for O2
992 X 22.4 = 2.2x10^4L. And thats not correct.

Please could you tell me what i am doing wrong?

[Mitch]

Don't rockets expel the products away from them. So perhaps the H₂ spent was 2 kg. Your reaction equation is wrong, the final product is H₂O.

[mike]

2H₂ + O₂ ----> 2H₂O

And then you have to redo your math

[awnashs]

thank you very much