The residue obtained on strongly heating 2.76 g Ag₂CO₃ is

$\left[{\mathrm{Ag}}_2{\mathrm{CO}}_3\stackrel{∆}{\to }\mathrm{Ag}+{\mathrm{CO}}_2+{\mathrm{O}}_2\right]$

Atomic mass of Ag = 1008

$\begin{array}{l}{\mathrm{Ag}}_2{\mathrm{CO}}_3\stackrel{ }{\to }2\mathrm{Ag}+{\mathrm{CO}}_2\uparrow +{\mathrm{O}}_2\uparrow \\ (\mathrm{Mw}=276\mathrm{g})(2\times 108\mathrm{g})\\ \mathrm{The} \mathrm{residue} \mathrm{is} \mathrm{due} \mathrm{to} \mathrm{Ag}\\ 276\mathrm{g} \mathrm{of} {\mathrm{Ag}}_2{\mathrm{CO}}_3 = 2 \times 108 \mathrm{g} \mathrm{Ag}\\ 2.76 \mathrm{g} \mathrm{of} {\mathrm{Ag}}_2{\mathrm{CO}}_3=\frac{2\times 108\times 2.76}{276}=2.16 \mathrm{g}\end{array}$