Question

$276\mathrm{g}$ of silver carbonate on being strongly heated yield ___.

Answer 1

Step 1: Calculation of molar mass of silver carbonate

• $\mathrm{Molar}\mathrm{mass}\mathrm{of}\mathrm{silver}=108\mathrm{g}/\mathrm{mol}$

• $\mathrm{Molar}\mathrm{mass}\mathrm{of}\mathrm{carbon}=12\mathrm{g}/\mathrm{mol}$
• $\mathrm{Molar}\mathrm{mass}\mathrm{of}\mathrm{oxygen}=16\mathrm{g}/\mathrm{mol}$
• $$\begin{gathered} \mathrm{Molecular}\mathrm{mass}\mathrm{of}\mathrm{silver}\mathrm{carbonate} \\ {\mathrm{Ag}}_2{\mathrm{CO}}_3=(108*2)+12+(16*3) \\ =276\mathrm{g}{\mathrm{mol}}^{-1} \end{gathered}$$
• Only silver will be left after strongly heating silver carbonate, and other products will be in gaseous form.

Step 2: Calculation of mass of silver produced

• The reaction of strongly heating silver carbonate will take place as follows
  $\mathrm{A}{\mathrm{g}}_2\mathrm{C}{\mathrm{O}}_3\stackrel{\mathrm{heat}}{\left(\mathrm{s}\right)\to }2\mathrm{Ag}\left(\mathrm{s}\right)+\mathrm{C}{\mathrm{O}}_2\left(\mathrm{g}\right)+\frac{1}{2}{\mathrm{O}}_2\left(\mathrm{g}\right)$
• The mass of silver obtained will be as follows

$\mathrm{Mass}\mathrm{of}\mathrm{Ag}\mathrm{yield}=\mathrm{molecular}\mathrm{mass}\mathrm{of}{\mathrm{Ag}}_2{\mathrm{CO}}_3-\mathrm{molecular}\mathrm{mass}\mathrm{of}\mathrm{carbon}\mathrm{dioxide}-(\frac{1}{2}*\mathrm{molar}\mathrm{mass}\mathrm{of}\mathrm{oxygen}\mathrm{gas})$

$$\begin{gathered} \mathrm{Mass}\mathrm{of}\mathrm{Ag}=276-(12+16+16)-\frac{1}{2}*(16+16) \\ \mathrm{Mass}\mathrm{of}\mathrm{Ag}\mathrm{obtained}=276-44-16 \end{gathered}$$

$\mathrm{Mass}\mathrm{of}\mathrm{Ag}\mathrm{obtained}=216\mathrm{g}$

• Hence, $276\mathrm{g}$ of silver carbonate on being strongly heated yield $216\mathrm{g}$ of silver.