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

the answers are

c and c