Question

Imagine that you have a 5.00 l gas tank and a 2.50 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 115 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. express your answer with the appropriate units.

Answer 1

To run out of oxygen and acetylene at the same time, fill the acetylene tank to a pressure of 46 atm when the oxygen tank is filled to 115 atm.

Step-by-step explanation:

To ensure that you run out of oxygen and acetylene at the same time, you need to know the ratio of the number of moles of oxygen to the number of moles of acetylene in the balanced chemical equation. From the balanced equation given, 2 C₂H₂ + 5O₂ → 4CO₂ + 2H₂O, it can be seen that 2 moles of acetylene react with 5 moles of oxygen. Therefore, the ratio of moles of oxygen to moles of acetylene is 5:2.

If you fill the larger tank with oxygen to a pressure of 115 atm, you should fill the acetylene tank to a pressure of (115 atm) * (2/5) = 46 atm to ensure that you run out of each gas at the same time.

Answer 2

We consider both gases are at the same temperature and an ideal behavior, then they follow the relation:
(P * V) / T = constant
Now we want to have the same quantity in both tank, and as the larger tank has double volume than the smaller, we will need to introduce the acetylene at double pressure to have the same quantity.
So then pressure of acetylene will be 230 atm.