What are the coefficients that belong in the blanks to balance the following chemical equation?

__ Silver (I) Iodide + __ Sodium sulfide - -> __ Silver (I) sulfide + __ Sodium Iodide

2AgI + 1Na₂S ⟶ 1Ag₂S + 2NaI

Explanation:

silver (I) iodide + sodium sulfide ⟶ silver (I) sulfide + sodium iodide

1. Convert the word equation to a chemical equation:

AgI + Na₂S ⟶ Ag₂S + NaI

2. Put a 1 in front of the most complicated-looking formula (Na₂S?):

AgI + 1Na₂S ⟶ Ag₂S + NaI

3. Balance Na:

We have fixed 2 Na on the left. We need 2 Na on the right. Put a 2 in front of NaI.

AgI + 1Na₂S ⟶ Ag₂S + 2NaI

4. Balance S:

We have fixed 1 S on the left. We need 1 O on the right. Put a 1 in front of Ag₂S.

AgI + 1Na₂S ⟶ 1Ag₂S + 2NaI

5. Balance Ag:

We have fixed 2Ag on the right. We need 2 Ag on the left. Put a 2 in front of AgI.

2AgI + 1Na₂S ⟶ 1Ag₂S + 2NaI

Every formula now has a coefficient. The equation should be balanced.

6. Check that atoms balance:

Atom On the left On the right

Ag 2 2

I 2 2

Na 2 2

S 1 1

The balanced equation is

2AgI + 1Na₂S ⟶ 1Ag₂S + 2NaI