[mybad4990]

Ok i need some help here, not asking anyone to do this for me, but there are alot of formulas involved here, apparently, and I don't know where to start.

Okay, you have a basketball that is 29.5 inches in circumference, and it is injected with nitrogen at 9 psi at room temperature(25 C) what is the mass in grams of the air inside the basketball?

I gotta hand this in tomorrow, so some help ASAP would be greatly appreciated.

[Loyal]

Ok for starters.   You need an equation that links Temperature, Pressure, and the amount of gas present correct?

[mybad4990]

Yeah. that would be the ideal gas law, right?

[Borek]

Yes. Calculate number of moles of gas first.

[mybad4990]

Ah ok, i think im getting the gist of it. I had to find the volume first(converting my temperature to kelvin and my pressure to atm)

P=.6122 atm
V=39.983 L
T=298.15

I used this to find the number of moles, which was 9.99 X 10^-2

What now, do I just convert my mols to mass?

[plankk]

What about molar mass?

[mybad4990]

Well we know that the molar mass of element is the mass of 1 g of the substance, I just multiplied the number of mols times the molar mass (14.01 g/mol)

9.99 X 10^-2 times 14.01=1.399599 grams.

Correct?

[plankk]

But nitrogen occurs as two-atoms molecules.

And I also don't know how you counted such volume.

[mybad4990]

got my decimal places wrong when doing the math =/

but thanks for the help.

[Borek]

Well we know that the molar mass of element is the mass of 1 g of the substance

No, mass of 1 g is 1 g, I suppose you meant mass of 1 mole

[sjb]

Ah ok, i think im getting the gist of it. I had to find the volume first(converting my temperature to kelvin and my pressure to atm)

P=.6122 atm
...

Would this not be 9 psi above ambient, else the ball will just implode?