Ammonia can be obtained by heating any ammonium salt with a base.
\begin{array}{l}
\Rightarrow\left(\mathrm{NH}_4\right)_2 \mathrm{SO}_4+2 \mathrm{NaOH} \underset{\Delta}{\longrightarrow} \mathrm{Na}_2 \mathrm{SO}_4+2 \mathrm{NH}_3+2 \mathrm{H}_2 \mathrm{O} \\
\Rightarrow 2 \mathrm{NH}_4 \mathrm{Cl}+\mathrm{Ca}(\mathrm{OH})_2 \underset{\Delta}{\longrightarrow} \mathrm{CaCl}_2+2 \mathrm{NH}_3+2 \mathrm{H}_2 \mathrm{O}
\end{array}