\documentclass[10pt]{article} \pagestyle{empty} \parindent=0pt \parskip=.1in \newcommand\hs{\hspace{6pt}} \begin{document} \centerline{\textbf{The Isothermal Bulk Modulus}} \bigskip \noindent We have the following equations of state for a \emph{monatomic ideal gas}. The first is the famous ideal gas law. The second is the internal energy of a \emph{monatomic} ideal gas. The third is the Sackur-Tetrode equation for entropy, which is true for any ideal gas. $$ pV = N k_B T $$ $$ U = \frac32 N k_B T $$ $$ S = N k_B \left\{ \ln\left[ \frac{V}{N} \left(\frac{m U}{3\pi N\hbar^2}\right)^\frac32 \right] + \frac52 \right\} $$ Using the above equations, find the isothermal bulk modulus, which you can think of them as an \emph{intensive} spring constant for a three-dimensional material. The Isothermal Bulk Modulus is $$ b_T = -V\left(\frac{\partial p}{\partial V}\right)_{T} $$ Now find the \emph{adiabatic} bulk modulus, which involves holding the \emph{entropy} constant: $$ b_S = -V\left(\frac{\partial p}{\partial V}\right)_{S} $$ \vfill \noindent \vfill \leftline{\textit{by David Roundy}} \leftline{\copyright DATE David Roundy} \end{document}