Acetylene torches are used for welding. These torches use a mixture of acetylene
ID: 863312 • Letter: A
Question
Acetylene torches are used for welding. These torches use a mixture of acetylene gas, C2H2, and oxygen gas, O2 to produce the following combustion reaction: 2C2H2(g)+5O2(g)?4CO2(g)+2H2O(g)
Imagine that you have a 7.00L gas tank and a 4.50L 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 135atm , 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.
Explanation / Answer
Hi,
the mole ratio is 2:5
and n = PV/RT
so
n1/n2 = (PV/RT)_1 / (PV/RT)_2
the R's and T's cancel (constant)
so
n1/n2 = P1*V1 / P2*V2
so
2/5 = P1*4.50 / 135*7.00
P1 = 84 atm