Final answer:
Heating a recovery cylinder with an open flame would likely increase the gas pressure inside, potentially leading to an explosion or the bursting of the cylinder due to the sudden increase in temperature and resultant pressure.
Step-by-step explanation:
When a recovery cylinder is heated with an open flame, it is exposed to a high temperature which will increase the pressure of the gas inside as per the ideal gas law PV = NkBT. This increase in temperature, while the cylinder volume remains constant, will cause the gas pressure to spike. In scenarios involving combustible gases like isobutane, this increase in pressure can become dangerous and may result in an explosion or bursting of the cylinder.
This is because heating can characterize burning fuel not only as a thermal action but also as a series of reactions leading to an explosion. In the case of flash-heating, like the ignition in an internal combustion engine, it can result in the piston being rapidly pushed away due to the sudden increase in pressure, demonstrating the conversion of thermal energy into mechanical work.