A weather balloon is inflated to a volume of 28.2 L at a pressure of 755 mmHg an
ID: 968608 • Letter: A
Question
A weather balloon is inflated to a volume of 28.2 L at a pressure of 755 mmHg and a temperature of 32.1 C. The balloon rises in the atmosphere to an altitude, where the pressure is 375 mmHg and the temperature is -14.7 C. Assuming the balloon can freely expand, calculate the volume of the balloon at this altitude.
2. A gas mixture with a total pressure of 760 mmHg contains each of the following gases at the indicated partial pressures: CO2, 129 mmHg ; Ar, 229 mmHg ; and O2, 187 mmHg . The mixture also contains helium gas.
What is the partial pressure of the helium gas?
What mass of helium gas is present in a 13.7-L sample of this mixture at 283 K ?
Explanation / Answer
1) P1V1/T1 = P2V2/T2
(28.2*0.993 / 305.25) = (0.493*V2/258.45)
V2 = final volume = 48.1 L
2)
partial pressure of He = 760 - (129+229+187) =215 mmhg
= 215/760 = 0.283 atm
w= mass of Helium = PVM/RT = (0.283*13.7*4/(0.0821*283)) = 0.667 grams