agno3 (AgNO3): name, ions, oxidation states, molar mass, and percent composition
The formula AgNO3 indicates a compound made from silver (Ag) and the polyatomic nitrate group (NO3). In general chemistry, AgNO3 is treated as an ionic salt consisting of a metal cation and a polyatomic anion.
Core idea. For salts with polyatomic ions, the polyatomic unit (here, nitrate) stays intact as an ion; naming and charge balance are done using the ion charges.
1) Identify the ions in agno3
- Metal cation: silver typically forms the ion Ag+ in common ionic compounds.
- Polyatomic anion: nitrate is the ion NO3−.
2) Verify charge balance and write the formula unit
Ionic compounds are electrically neutral overall, so the total positive charge must equal the total negative charge. Ag+ has charge \(+1\) and NO3− has charge \( -1 \), so one of each gives neutrality:
\[ (+1) + (-1) = 0 \]
Therefore, the simplest neutral formula is AgNO3.
3) Name agno3 using ionic nomenclature
Naming a salt with a polyatomic ion follows: cation name + anion name. Ag+ is “silver” (also acceptable: silver(I)), and NO3− is “nitrate”.
Name: silver nitrate
4) Determine oxidation states in AgNO3
For ionic compounds, the cation oxidation state equals its ionic charge: silver is \(+1\). In nitrate, oxygen is typically \( -2 \). The nitrate ion has total charge \( -1 \), so nitrogen must be \(+5\):
\[ x + 3(-2) = -1 \] \[ x - 6 = -1 \quad \Rightarrow \quad x = +5 \]
5) Compute molar mass (formula mass) of agno3
Using standard atomic masses to typical textbook precision: Ag \(= 107.8682\), N \(= 14.0067\), O \(= 15.999\) (in g·mol\(^{-1}\)).
| Element | Atoms in AgNO3 | Atomic mass (g·mol\(^{-1}\)) | Mass contribution (g·mol\(^{-1}\)) |
|---|---|---|---|
| Ag | 1 | 107.8682 | 107.8682 |
| N | 1 | 14.0067 | 14.0067 |
| O | 3 | 15.999 | 47.997 |
| Total | — | — | 169.8719 |
\[ M(\mathrm{AgNO_3}) = 107.8682 + 14.0067 + 3(15.999) = 169.8719\ \text{g·mol}^{-1} \approx 169.87\ \text{g·mol}^{-1} \]
6) Percent composition of Ag, N, and O in AgNO3
Mass percent is computed by dividing each element’s contribution by the molar mass and multiplying by \(100\%\).
\[ \%\,\mathrm{Ag} = \frac{107.8682}{169.8719}\times 100\% \approx 63.50\% \] \[ \%\,\mathrm{N} = \frac{14.0067}{169.8719}\times 100\% \approx 8.25\% \] \[ \%\,\mathrm{O} = \frac{47.997}{169.8719}\times 100\% \approx 28.25\% \]
| Element | Mass contribution (g·mol\(^{-1}\)) | Mass percent |
|---|---|---|
| Ag | 107.8682 | 63.50% |
| N | 14.0067 | 8.25% |
| O | 47.997 | 28.25% |
Visualization: how agno3 is built from ions
Additional chemical context (aqueous behavior)
In water, silver nitrate is commonly treated as an electrolyte that dissociates into its ions:
\[ \mathrm{AgNO_3}(aq) \rightarrow \mathrm{Ag^+}(aq) + \mathrm{NO_3^-}(aq) \]
Final results for agno3
- Name: silver nitrate
- Ions: Ag+ and NO3−
- Oxidation states: Ag \(+1\), N \(+5\), O \( -2 \)
- Molar mass: \(169.87\ \text{g·mol}^{-1}\)
- Percent composition: Ag \(63.50\%\), N \(8.25\%\), O \(28.25\%\)