[viet]

A 150.0 L helium tank contains pure helium at a pressure of 1850 psi and a temperature of 298 K.
How many 3.5 L helium balloons can be filled from the helium in the tank? (Assume an atmospheric pressure of 1.0 atm and a temperature of 298 K.)

i used the gas law formula: PV = nRT to find the number of moles of the 150L tank, then find the number of moles of the 3.5L balloon. Then divide the number of moles in tank by the balloon, and got 1.02x10^27, the answer is wrong, can someone help me with this?

[enahs]

Show your math.
Hint, UNITS!

[viet]

heres the calculation:
for balloon: n = PV/RT = (1.0atm*3.5L)/(.0821(L*atm/mol*K)298K) = 0.143 moles in 1 balloon

for 150L tank: 1850 psi (68.046x10^(-3) atm / 1psi) = 125.885 atm
n = PV/RT = (125.885atm*15.0L)/(.0821(L*atm/mole*k)298K) = 771.8 moles in tank.

then 771.8 moles / 0.143 moles = 5397.2 ~5.4x10^4

[Borek]

Seems much better.

[viet]

5397.2 is the wrong answer. someone help

[Naumans]

nope this answer should be right, i did the calc and found the exact answer to be
 5395.075