(NH4)2S2O3 🔥→ 2NH3↑ + H2SO3 + S
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- Decomposition of ammonium thiosulfate
Decomposition of ammonium thiosulfate yields ammonia, sulfurous acid, and (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 | 1 | – | Thermally decomposable Oxoacid salt |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| NH3 | Ammonia | 2 | – | – |
| H2SO3 | Sulfurous acid | 1 | Reduced | – |
| 1 | Oxidized | – |
Thermodynamic changes
Changes in aqueous solution (1)
- Decomposition of ammonium thiosulfate
| 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 | 216.1 | – | – | – |
per 1 mol of | 216.1 | – | – | – |
per 1 mol of | 108.0 | – | – | – |
per 1 mol of | 216.1 | – | – | – |
| 216.1 | – | – | – |
Changes in aqueous solution (2)
- Decomposition of ammonium thiosulfate
- (NH4)2S2O3Aqueous solution2NH3↑Un-ionized aqueous solution + H2SO3Un-ionized aqueous solution + Crystalline solidrhombic🔥⟶
| 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 | 147.7 | – | – | – |
per 1 mol of | 147.7 | – | – | – |
per 1 mol of | 73.85 | – | – | – |
per 1 mol of | 147.7 | – | – | – |
| 147.7 | – | – | – |
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 |
|---|---|---|---|---|
| NH3 (g) | -46.11[1] | -16.45[1] | 192.45[1] | 35.06[1] |
| NH3 (ao) | -80.29[1] | -26.50[1] | 111.3[1] | – |
| H2SO3 (ao) | -608.81[1] | -537.81[1] | 232.2[1] | – |
| (cr) rhombic | 0[1] | 0[1] | 31.80[1] | 22.64[1] |
| (cr) monoclinic | 0.33[1] | – | – | – |
| (g) | 278.805[1] | 238.250[1] | 167.821[1] | 23.673[1] |
* (g):Gas, (ao):Un-ionized aqueous solution, (cr):Crystalline solid
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°, -46.11 kJ · mol−1
- ^ ΔfG°, -16.45 kJ · mol−1
- ^ S°, 192.45 J · K−1 · mol−1
- ^ Cp°, 35.06 J · K−1 · mol−1
- ^ ΔfH°, -80.29 kJ · mol−1
- ^ ΔfG°, -26.50 kJ · mol−1
- ^ S°, 111.3 J · K−1 · mol−1
- ^ ΔfH°, -608.81 kJ · mol−1
- ^ ΔfG°, -537.81 kJ · mol−1
- ^ S°, 232.2 J · K−1 · mol−1
- ^ ΔfH°, 0 kJ · mol−1
- ^ ΔfG°, 0 kJ · mol−1
- ^ S°, 31.80 J · K−1 · mol−1
- ^ Cp°, 22.64 J · K−1 · mol−1
- ^ ΔfH°, 0.33 kJ · mol−1
- ^ ΔfH°, 278.805 kJ · mol−1
- ^ ΔfG°, 238.250 kJ · mol−1
- ^ S°, 167.821 J · K−1 · mol−1
- ^ Cp°, 23.673 J · K−1 · mol−1