A group of educators have built an entire learning environment for the free online Statistical and Thermal Physics textbook by H. Gould and J. Tobochnik.
Free Thermodynamics Textbooks
Thermodynamics is the physical science that studies outcomes of fluctuations in pressure, temperature and volume on material bodies at a scale which can be observed or measured without mechanical assistance through measuring and analyzing the collective motion of their particles. Free online thermodynamics textbooks are used primarily by students studying physics but some place Chemical Thermodynamics topics under a chemistry curriculum. Here on The Free Textbook List they will be listed together here in one convenient place. Additional related branches include Classical Thermodynamics, Statistical Thermodynamics and Equilibrium Thermodynamics.
Students of thermodynamics will need good laboratory skills as well as a strong mathematical background.