Chemical-engineering Students

Fugacity is supposed to be easily understood, especially because that was the main purpose of its invention. Lets just get some history straight first. In the beginning there was chemical potential, usually denoted as  μ, and defined as: Definition of Chemical Potential with G and n i being the Gibbs free energy and moles of compound i respectively. As you see  μ is used to describe the Gibbs free energy, and if you know thermodynamics you should know that Gibbs is used to describe chemical equilibrium in pure and mixed systems, if you didn't know, this is very important. The problem however with chemical potential is that it is an abstract concept, like the amount of honest bankers, in other words, it can not be directly measured. In its stead fugacity was invented by one, G.N. Lewis (Also famous for his Lewis dot structure of molecules and his mustache). G.N. Lewis Partial fugacity, is the pseudo-pressure exerted by the mixture of molecules in the vapor phase, and it i

"Why can't a isothemal process be adiabatic?" This was the question my housemate, that studies geology and geography, asked me while studying for his thermodynamics test. As a chemical engineering student I was suppose to be able to answer him immediately, but it took me some pondering to give him a good answer. Lets consider the isothermal expansion of gas, and lets use the convention used by most thermodynamic textbooks that work (W) done by the system on the environment is said to be negative. Consider the diagram and the formula used for work done by isothermal expansion of an ideal gas and the heat formula. Isothermal expansion Work done by isothermal expansion of an ideal gas Heat formula for expansion of an ideal gas in a closed system And because, for reversible isothemal expansion the following is true: For reversible isothermal expansion  thus we can see that Q = -W, and W is not equal to 0 because the volume has changed, that means th