Christian Binek

Thermodynamics and Statistical Mechanics: Integrated Approach, An

Learn classical thermodynamics alongside statistical mechanics with this fresh approach to the subjects. Molecular and macroscopic principles are explained in an integrated, side-by-side manner to give students a deep, intuitive understanding of thermodynamics and equip them to tackle future research topics that focus on the nanoscale. Entropy is introduced from the get-go, providing a clear explanation of how the classical laws connect to the molecular principles, and closing the gap between the atomic world and thermodynamics. Notation is streamlined throughout, with a focus on general concepts and simple models, for building basic physical intuition and gaining confidence in problem analysis and model development. Well over 400 guided end-of-chapter problems are included, addressing conceptual, fundamental, and applied skill sets. Numerous worked examples are also provided together with handy shaded boxes to emphasize key concepts, making this the complete teaching package for students in chemical engineering and the chemical sciences.

Reversible and Irreversible Processes

• Chemical thermodynamics is concerned with energy relationships in chemical reactions. • We consider enthalpy. • We also consider entropy in the reaction. • Recall the first law of thermodynamics: energy is conserved. ΔE= q + w • where ΔE is the change in internal energy, q is the heat absorbed by the system from the surroundings, and w is the work done. • Any process that occurs without outside intervention is a spontaneous process. • When two eggs are dropped they spontaneously break. • The reverse reaction (two eggs leaping into your hand with their shells back intact) is not spontaneous. • We can conclude that a spontaneous process has a direction. • A process that is spontaneous in one direction is nonspontaneous in the opposite direction. • Temperature may also affect the spontaneity of a process. • A reversible process is one that can go back and forth between states along the same path. • The reverse process restores the system to its original state. • The path taken back to the original state is exactly the reverse of the forward process. • There is no net change in the system or the surroundings when this cycle is completed. • Completely reversible processes are too slow to be attained in practice. • Consider the interconversion of ice and water at 1 atm, 0 o C. • Ice and water are in equilibrium. • We now add heat to the system from the surroundings. • We melt 1 mole of ice to form 1 mole of liquid water. q=ΔH fus • To return to the original state we reverse the procedure. • We remove the same amount of heat from the system to the surroundings. • An irreversible process cannot be reversed to restore the system and surroundings back to their original state. • A different path (with different values of q and w) must be taken. • Consider a gas in a cylinder with a piston. • Remove the partition and the gas expands to fill the space. • No P-V work is done on the surroundings. • w = 0 • Now use the piston to compress the gas back to the original state. • The surroundings must do work on the system. • w > 0 • A different path is required to get the system back to its original state. • Note that the surroundings …