Ethylene (CH2CH2) is the starting point for a wide array of industrial chemical syntheses. For example, worldwide about 8.0 x 10^10 of polyethylene are made from ethylene each year, for use in everything from household plumbing to artificial joints. Natural sources of ethylene are entirely inadequate to meet world demand, so ethane (ch2ch2) from natural gas is "cracked" in refineries at high temperature in a kinetically complex reaction that produces ethylene gas and hydrogen gas.

Suppose an engineer studying ethane cracking fills a 65.0Lreaction tank with 26.0 atm of ethane gas and raises the temperature to750 degree celcius. He believes Kp=1.0 at this temperature.

Calculate the percent by mass of ethylene the engineer expects to find in the equilibrium gas mixture.

Round your answer to significant digits.