I think this is what you wanted, so good luck!
Robert Boyle, the 17th century British chemist, first noticed that the volume of a given amount of gas is inversely proportional to its pressure when kept at a constant temperature. When working with ideal gases we use PV = nRT, but remember n, R, and T are all constant. Therefore we have:
PV(before) = PV(after)
P(0.5650) = (715.1)(1.204)
Uranium-238 is the element that undergoes decay to yield uranium-234
