# Question #9ccea

Sep 23, 2014

The first step to answer this question is to ID which reaction types will occur.

#### Explanation:

Zn + $C u B {r}_{2}$ -> will be a single replacement rxn

${H}_{2}$ + $C {l}_{2}$ -> will be a synthesis rxn

$M g C {O}_{3}$ -> will be a decomposition rxn

KCl + $A g N {O}_{3}$ -> this is a precipitation rxn

Zn + $C u B {r}_{2}$ ->Cu + $Z n B {r}_{2}$ (need to know the oxidation of zinc is +2 = memorize this!)

${H}_{2}$ + $C {l}_{2}$ -> HCl (need to know that H is +1 and Cl is -1)

$M g C {O}_{3}$ -> MgO + $C {O}_{2}$ (need to know that Mg is +2 and O is -2 and that carbonates produce $C {O}_{2}$ and oxides when they decompose

KCl + $A g N {O}_{3}$ -> $K N {O}_{3}$ + AgCl (need to know that K is +1 and $N {O}_{3}$ is -1)
Since both $K$ & $N {O}_{3}$ are in soluble compounds on both sides of this last equation, we call them spectator ions.
The net ionic equation for this reaction is:
$C {l}^{-}$(aq)$+ A {g}^{+}$(aq)$\to A g C l$(s)

You should balance the equations as well!

Here is a video which discusses the topic of reaction prediction.

video from:Noel Pauller