A cylinder of compressed Oxygen is carried on a spacecraft headed for Mars. The compressed gas cylinder has a volume of 10,000 L and is filled to a pressure of 200 atm at 273 K. The maximum pressure the cylinder can hold is 1000 atm.
The molar mass of Oxygen is 32 g/mol.
Boltzmann's constant = 1.38×10-23 J/K
Avogadro's constant = 6.02×1023 1/mol
1 L = 1000 cm3 = 0.001 m3
R = 8.31 J/mol K

(a) Assuming that Oxygen is an ideal gas, what is the maximum temperature in Kelvin that the tanks can withstand before bursting?

Temp = 1365 K

(b) What is the rms velocity of the oxygen molecules in the cylinder at it's maximum temperature?

v = 1031.033 m/s

(c) The contents of the cylinder is then entirely transferred to a partially filled holding tank of volume 10,000 L originally at pressure 2 atm and 300 K. What is the new pressure in the holding tank at 300 K?

I can't GET PART C, please help!

I'm not getting the same answer as yours for part b...

Could you show us what you did? I might find out what I'm doing wrong.

c) For part c, I believe you have to work out the number of moles of oxygen previously in the holding tank.

Then, add those to the number of moles from the cylinder. Work out the new pressure using

PV = nRT

You have the volume, the new number of moles, the ideal gas constant and the temperature. :)

For part C you need to find the total number of moles of gas in the combined tank, which is the sum of moles of gas 1 plus gas 2. Using the ideal gas law, you can determine these quantities as follows:


n_1 = \frac {P_1V_1} {RT_1} = \frac {200atm\ \times\ 10000L}{R\ \times\ 273K}\\
n_1 = \frac {P_2V_2} {RT_2}= \frac {2atm\ \times \ 10000L}{R\ \times\ 300K}


Use the combined [math] (n_1 + n2) in the Ideal Gas Law to find the pressure in tank 2 at 300K when both gasses are combined.