Answer to Question #299723 in Physical Chemistry for HRMSCA

Question

Suppose that you are travelling in the Space Shuttle Endeavor on a journey to Mars. The atmosphere (of the vehicle) consists of 20% oxygen and 80% helium by volume. It was noticed before take off from the Kennedy Space Center that there is a small leakage which if unchecked, would lead to a continual loss of gas at a rate of 0.05 atm/day through effusion. If the temperature in the space shuttle is maintained at 22°C and the volume of the vehicle is 15,000 liters. Calculate the amounts of helium and oxygen in grams that must be stored on a 5-day journey to allow for the leakage.

Answer 1

Change in pressure

$0.05 ×5=0.25atm$

$PV = nRT$

$0.25 × 15000= n ×0.08205×(22+273.15)$

$n=154.8495\>moles$

Mass of Oxygen

$=\frac{20}{100}×154.8495×32=991\>g$

Mass of Helium

$\frac{80}{100}×154.8495×4=495.5g$