Question #bf7ca

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Nathan L.
Jun 6, 2017

Zn(s)+2AgNO3(aq)→Zn(NO3)2(aq)+2Ag(s)

Explanation:

Let's look at our reactants and products,

Reactants

  • zinc metal. We write this in the chemical equation as the chemical symbol for zinc, Zn. Often times a species in a chemical equation is followed by its physical state in parentheses:

(s) for a solid substance

(l) for a liquid substance

(g) for a gaseous substance

(aq) for a substance dissolved in aqueous solution

Most periodic tables will indicate the state of matter for each element, usually via a color code. Zinc is a solid metal, so we can follow it with the symbol (s) in the reaction

  • silver nitrate. This is a compound formed from the electrostatic attraction between a cationic silver atom, Ag+, and the anionic nitrate species, NO−3, so its formula is AgNO3.

As for the state of matter, we must realize something about this reaction. Most all ionic substances are solid at room temperature, but for this reaction we won't write (s) next to it, and here's the simple reason why. When two pure solids are interacting, nothing chemically is really happening; you can squeeze the two substances together, but no new substances will form. Therefore, it is implied that the AgNO3 species is dissolved in aqueous solution, so we follow it with (aq).

Products

  • zinc nitrate. This compound is formed from the attraction between the zinc ion Zn2+ and the nitrate ion, so its formula is Zn(NO3)2.

Its state of matter is the same situation as the silver nitrate, and is dissolved in solution, so it's followed by (aq).

  • silver metal. Likewise for zinc metal, this is simply the chemical symbol of silver, Ag followed by its state of matter, solid, so it is Ag(s)

We can now form an unbalanced (no coefficients) chemical equation from this:

Zn(s)+AgNO3(aq)→Zn(NO3)2(aq)+Ag(s)

If you'll notice, there are two nitrate ions on the right side, and one on the left. To balance the nitrate species, we can place a 2 before the silver nitrate on the left side:

Zn(s)+2AgNO3(aq)→Zn(NO3)2(aq)+Ag(s)

What you may notice now is that now the silvers are unbalanced; there are two on the left and one on the right. We can fix this by placing a 2 in front of the silver on the right side:

Zn(s)+2AgNO3(aq)→Zn(NO3)2(aq)+2Ag(s)

Now, all the species are present equally on both sides of the reaction arrow, so this equation is balanced.

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