Question

For the decomposition reaction `2Ag_2CO_3->4Ag+2CO_2+O_2`, how many moles of reactant undergo decomposition in order to produce 6.0 moles of `Ag`?

Answer 1

`Ag_2CO_3 + Delta rarr Ag_2O + CO_2(g)uarr`

Explanation:

The reaction above correctly represents thermal decomposition of a metal carbonate. The carbonate gives metal oxide and carbon dioxide under STRONG heating. You are not going to get silver metal unless you get it all into solution and add some reductant (maybe copper). Of course, you could do this in a forge, but it would be very difficult to smelt; and you'd still have to add a reductant.

Instead, we could make silver nitrate:

`Ag_2O + 2HNO_3(aq) rarr 2AgNO_3(aq) + H_2O(l)`

Silver nitrate would be relatively easy to reduce.

Answer 2

2/4 = x/6
Solve for 'x'.

Explanation:

From your balanced reaction equation, possible or not, you take the coefficients of the molecules as their molar ratios. Therefore, your reaction shows that 2 moles of silver carbonate decompose into 4 moles of silver, 2 moles of carbon dioxide, and one mole of oxygen.

To find the ratio you want - moles of silver carbonate to produce 6 moles of silver, you just use a ratio equivalence with these values.
2/4 = x/6
Solve for 'x'.