Posted by Michelle on .
Imagine that you have a 5.50 L gas tank and a 3.50 L gas tank. You need to fill one tank with oxygen and the other with acetylene to use in conjunction with your welding torch. If you fill the larger tank with oxygen to a pressure of 155 atm, to what pressure should you fill the acetylene tank to ensure that you run out of each gas at the same time? Assume ideal behavior for all gases.

Chemistry 
bobpursley,
find the number of moles of O2
n=PV/RT
now balance the equation, and look at the mole ratio. How many moles of acetylene do you need for n moles of O2?
now, find the pressure
P=molesAcy*RT/V