0.92 gram of ${\mathrm{Ag}}_2{\mathrm{CO}}_3$ is heated strongly beyond its melting point. After heating the amount of residue is ____?

Applying POAC, we have

$\begin{array}{l}{\mathrm{Ag}}_2{\mathrm{CO}}_3\to \mathrm{Ag}+{\mathrm{CO}}_2+{\mathrm{O}}_2\\ 2\times n_{{\mathrm{Ag}}_2{\mathrm{CO}}_3}=1\times n_{\mathrm{Ag}}\\ 2\times \frac{0.92}{2\times 108+60}=1\times \frac{\mathrm{W}}{108}\\ \frac{2\times 0.92}{216+60}=\frac{W}{108}\\ W=\frac{108\times 2\times 0.92}{276}=0.72\mathrm{gram}\end{array}$