Chapter 1 Summary

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• The first law of thermodynamics states that %%energy%% cannot be created or destroyed, but it can be converted from one form into another.
• Engineers design products and processes that accomplish specific tasks or meet specific needs. Converting and using energy as efficiently as possible is a fundamental concern in design.
• Energy can be stored in the forms of internal energy, kinetic energy and potential energy.
• Energy can be transferred in the forms of heat (Q) and work (W).
• Work is the energy required to move something through a distance against an opposing force.
• Work occurs when there is an imbalance in force, and heat transfer occurs when there is an imbalance in temperature.
• For our purposes, three forms of work are significant: flow work, shaft work, and expansion/contraction work.
• Solving problems is facilitated by defining a system. A system must have clear, unambiguous boundaries, such that we can recognize when mass or energy enters or leaves the system.
• W and Q are considered positive when energy is added to the system and negative when energy is removed from the system.
• Solving problems is often facilitated by defining a process, which has a clear beginning and a clear end.
• The initial state is a description of the system at the beginning of the process, and the final state is a description of the system at the end of the process.
• A closed system is one in which no matter enters or leaves the system, and an open system is one in which matter can cross the boundaries of the system.
• In an isolated system, neither matter nor energy crosses the boundaries of the system.
• An adiabatic process is one in which no heat is added or removed.
• An isothermal process is one in which temperature is constant with respect to time, and an isothermal system is one in which the temperature is uniform throughout the system.
• An isobaric process is one in which pressure is constant with respect to time, and an isobaric system is one in which the pressure is uniform throughout the system.
• An isochoric system has a constant volume.
• A system is at steady state if ALL properties of the system remain constant with respect to time.
• A system is at equilibrium when there is no driving force present that will cause the properties of the system to change.
• The driving forces for change that we are concerned with in chemical engineering thermodynamics are differences in temperature, pressure, and fugacity.
• It is possible for a system to be at steady state without being at equilibrium.