3(NH4)2S2O3 🔥→ 2NH4NO2 + 2HNO2 + 6H2S↑ + H2O
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- Decomposition of ammonium thiosulfate
Decomposition of ammonium thiosulfate yields ammonium nitrite, nitrous acid, hydrogen sulfide, and water (Other reactions are here). This reaction is an oxidation-reduction reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Decomposition of ammonium thiosulfate
General equation
- Thermal decomposition with redox
- Thermally decomposable substanceSelf redox agent🔥⟶ ProductOxidation product + ProductReduction product
- Thermal decomposition of oxoacid salt with redox
- Oxoacid saltSelf redox agent🔥⟶ ProductOxidation product + ProductReduction product
Oxidation state of each atom
- Decomposition of ammonium thiosulfate
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| (NH4)2S2O3 | Ammonium thiosulfate | 3 | Self redox agent | Thermally decomposable Oxoacid salt |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| NH4NO2 | Ammonium nitrite | 2 | Oxidized | – |
| HNO2 | Nitrous acid | 2 | Oxidized | – |
| H2S | Hydrogen sulfide | 6 | Reduced | – |
| H2O | Water | 1 | – | – |
Thermodynamic changes
Changes in aqueous solution (1)
- Decomposition of ammonium thiosulfate
- 3(NH4)2S2O3Aqueous solution2NH4NO2Ionized aqueous solution + 2HNO2Un-ionized aqueous solution + 6H2S↑Gas + H2OLiquid🔥⟶
| Standard enthalpy of reaction ΔrH° kJ · mol−1 | Standard Gibbs energy of reaction ΔrG° kJ · mol−1 | Standard entropy of reaction ΔrS° J · K−1 · mol−1 | Standard heat capacity of reaction at constant pressure ΔrCp° J · K−1 · mol−1 | |
|---|---|---|---|---|
per 1 mol of Equation | 1628.9 | – | – | – |
per 1 mol of | 542.97 | – | – | – |
per 1 mol of | 814.45 | – | – | – |
per 1 mol of | 814.45 | – | – | – |
per 1 mol of | 271.48 | – | – | – |
per 1 mol of | 1628.9 | – | – | – |
Changes in aqueous solution (2)
- Decomposition of ammonium thiosulfate
- 3(NH4)2S2O3Aqueous solution2NH4NO2Ionized aqueous solution + 2HNO2Un-ionized aqueous solution + 6H2S↑Un-ionized aqueous solution + H2OLiquid🔥⟶
| Standard enthalpy of reaction ΔrH° kJ · mol−1 | Standard Gibbs energy of reaction ΔrG° kJ · mol−1 | Standard entropy of reaction ΔrS° J · K−1 · mol−1 | Standard heat capacity of reaction at constant pressure ΔrCp° J · K−1 · mol−1 | |
|---|---|---|---|---|
per 1 mol of Equation | 1514.5 | – | – | – |
per 1 mol of | 504.83 | – | – | – |
per 1 mol of | 757.25 | – | – | – |
per 1 mol of | 757.25 | – | – | – |
per 1 mol of | 252.42 | – | – | – |
per 1 mol of | 1514.5 | – | – | – |
Thermodynamic data of reactants
| Chemical formula | Standard enthalpy of formation ΔfH° kJ · mol−1 | Standard Gibbs energy of formation ΔfG° kJ · mol−1 | Standard molar entropy S° J · K−1 · mol−1 | Standard molar heat capacity at constant pressure Cp° J · K−1 · mol−1 |
|---|---|---|---|---|
| (NH4)2S2O3 (aq) | -917.1[1] | – | – | – |
* (aq):Aqueous solution
Thermodynamic data of products
| Chemical formula | Standard enthalpy of formation ΔfH° kJ · mol−1 | Standard Gibbs energy of formation ΔfG° kJ · mol−1 | Standard molar entropy S° J · K−1 · mol−1 | Standard molar heat capacity at constant pressure Cp° J · K−1 · mol−1 |
|---|---|---|---|---|
| NH4NO2 (cr) | -256.5[1] | – | – | – |
| NH4NO2 (ai) | -237.2[1] | -111.6[1] | 236.4[1] | -17.6[1] |
| HNO2 (g) cis | -77.99[1] | -42.94[1] | 248.76[1] | 44.77[1] |
| HNO2 (g) trans | -80.12[1] | -45.24[1] | 249.22[1] | 46.07[1] |
| HNO2 (g) | -79.5[1] | -46.0[1] | 254.1[1] | 45.6[1] |
| HNO2 (ao) | -119.2[1] | -50.6[1] | 135.6[1] | – |
| H2S (g) | -20.63[1] | -33.56[1] | 205.79[1] | 34.23[1] |
| H2S (ao) | -39.7[1] | -27.83[1] | 121[1] | – |
| H2O (cr) | – | – | – | – |
| H2O (l) | -285.830[1] | -237.129[1] | 69.91[1] | 75.291[1] |
| H2O (g) | -241.818[1] | -228.572[1] | 188.825[1] | 33.577[1] |
* (cr):Crystalline solid, (ai):Ionized aqueous solution, (g):Gas, (ao):Un-ionized aqueous solution, (l):Liquid
References
List of references
- 1Janiel J. Reed (1989)The NBS Tables of Chemical Thermodynamic Properties: Selected Values for Inorganic and C1 and C2 Organic Substances in SI UnitsNational Institute of Standards and Technology (NIST)
- ^ ΔfH°, -917.1 kJ · mol−1
- ^ ΔfH°, -256.5 kJ · mol−1
- ^ ΔfH°, -237.2 kJ · mol−1
- ^ ΔfG°, -111.6 kJ · mol−1
- ^ S°, 236.4 J · K−1 · mol−1
- ^ Cp°, -17.6 J · K−1 · mol−1
- ^ ΔfH°, -77.99 kJ · mol−1
- ^ ΔfG°, -42.94 kJ · mol−1
- ^ S°, 248.76 J · K−1 · mol−1
- ^ Cp°, 44.77 J · K−1 · mol−1
- ^ ΔfH°, -80.12 kJ · mol−1
- ^ ΔfG°, -45.24 kJ · mol−1
- ^ S°, 249.22 J · K−1 · mol−1
- ^ Cp°, 46.07 J · K−1 · mol−1
- ^ ΔfH°, -79.5 kJ · mol−1
- ^ ΔfG°, -46.0 kJ · mol−1
- ^ S°, 254.1 J · K−1 · mol−1
- ^ Cp°, 45.6 J · K−1 · mol−1
- ^ ΔfH°, -119.2 kJ · mol−1
- ^ ΔfG°, -50.6 kJ · mol−1
- ^ S°, 135.6 J · K−1 · mol−1
- ^ ΔfH°, -20.63 kJ · mol−1
- ^ ΔfG°, -33.56 kJ · mol−1
- ^ S°, 205.79 J · K−1 · mol−1
- ^ Cp°, 34.23 J · K−1 · mol−1
- ^ ΔfH°, -39.7 kJ · mol−1
- ^ ΔfG°, -27.83 kJ · mol−1
- ^ S°, 121. J · K−1 · mol−1
- ^ ΔfH°, -285.830 kJ · mol−1
- ^ ΔfG°, -237.129 kJ · mol−1
- ^ S°, 69.91 J · K−1 · mol−1
- ^ Cp°, 75.291 J · K−1 · mol−1
- ^ ΔfH°, -241.818 kJ · mol−1
- ^ ΔfG°, -228.572 kJ · mol−1
- ^ S°, 188.825 J · K−1 · mol−1
- ^ Cp°, 33.577 J · K−1 · mol−1