Where can I find the standard molar entropy for ammonium bicarbonate?
“Standard Thermodynamic Properties of Chemical Substances”, in CRC Handbook of Chemistry and Physics, 90th Edition (CD-ROM Version 2010), David R. Lide, ed., CRC Press/Taylor and Francis, Boca Raton, FL. gives values for the standard molar enthalpy of formation $\Delta_\mathrm fH^\circ$, the standard molar Gibbs energy of formation $\Delta_\mathrm fG^\circ$, and the standard molar entropy $S^\circ$ (all at $T=298.15\ \mathrm K$ and $p=100\ \mathrm{kPa}=1\ \mathrm{bar}$) of crystalline ammonium hydrogen carbonate as follows.
$$\begin{align}
\Delta_\mathrm fH^\circ&amp;=-849.4\ \mathrm{kJ/mol}\\
\Delta_\mathrm fG^\circ&amp;=-665.9\ \mathrm{kJ/mol}\\
S^\circ&amp;=120.9\ \mathrm{J/(mol\ K)}
\end{align}$$