The name has it in itself that it deal with thermo (temperature) and dynamics (movement). Basically, thermodynamics, is the physics of motion as a result of heat. The heat warms up the material and the elements inside the material start to fidget and create energy and all these properties, thanks to science, can be determined and learned so that FE exam can be passed too. These properties are related to what phase the substance of interest is in (solid, liquid, or gas). Rumor has it that the substances can be categorized into more than these three phases as their properties vary so much even in one of the same phases noted above. This intro ignites our engine to learn about the properties of material.
Photo: Power plant chimneys @ Missouri S&T
The following subjects are supposed to be learned to solve the questions in FE exam:
Thermodynamics Laws
Entropy
Mixture of Gasses, Liquids, and Vapors
Combustion
Heat Transfer
Transport Phenomena
By the way, here is a link to the MIT open courses series on thermodynamics if somebody interested in watching a few videos on this subject, which are pretty nice and catchy lectures (accessed 9/14/2015).