(NH4)2S2O3 🔥→ N2H4 + H2S↑ + H2SO3
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- Decomposition of ammonium thiosulfate
Decomposition of ammonium thiosulfate yields hydrazine, hydrogen sulfide, and sulfurous acid (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 | Self redox agent | Thermally decomposable Oxoacid salt |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| N2H4 | Hydrazine | 1 | Oxidized | – |
| H2S | Hydrogen sulfide | 1 | Reduced | – |
| H2SO3 | Sulfurous acid | 1 | Reduced | – |
Thermodynamic changes
Changes in aqueous solution (1)
- Decomposition of ammonium thiosulfate
- (NH4)2S2O3Aqueous solutionN2H4Un-ionized aqueous solution + H2S↑Gas + H2SO3Un-ionized aqueous solution🔥⟶
| 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 | 322.0 | – | – | – |
per 1 mol of | 322.0 | – | – | – |
per 1 mol of | 322.0 | – | – | – |
per 1 mol of | 322.0 | – | – | – |
per 1 mol of | 322.0 | – | – | – |
Changes in aqueous solution (2)
- Decomposition of ammonium thiosulfate
- (NH4)2S2O3Aqueous solutionN2H4Un-ionized aqueous solution + H2S↑Un-ionized aqueous solution + H2SO3Un-ionized aqueous solution🔥⟶
| 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 | 302.9 | – | – | – |
per 1 mol of | 302.9 | – | – | – |
per 1 mol of | 302.9 | – | – | – |
per 1 mol of | 302.9 | – | – | – |
per 1 mol of | 302.9 | – | – | – |
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 |
|---|---|---|---|---|
| N2H4 (l) | 50.63[1] | 149.34[1] | 121.21[1] | 98.87[1] |
| N2H4 (g) | 95.40[1] | 159.35[1] | 238.47[1] | 49.58[1] |
| N2H4 (ao) | 34.31[1] | 128.1[1] | 138[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] | – |
| H2SO3 (ao) | -608.81[1] | -537.81[1] | 232.2[1] | – |
* (l):Liquid, (g):Gas, (ao):Un-ionized aqueous solution
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°, 50.63 kJ · mol−1
- ^ ΔfG°, 149.34 kJ · mol−1
- ^ S°, 121.21 J · K−1 · mol−1
- ^ Cp°, 98.87 J · K−1 · mol−1
- ^ ΔfH°, 95.40 kJ · mol−1
- ^ ΔfG°, 159.35 kJ · mol−1
- ^ S°, 238.47 J · K−1 · mol−1
- ^ Cp°, 49.58 J · K−1 · mol−1
- ^ ΔfH°, 34.31 kJ · mol−1
- ^ ΔfG°, 128.1 kJ · mol−1
- ^ S°, 138. 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°, -608.81 kJ · mol−1
- ^ ΔfG°, -537.81 kJ · mol−1
- ^ S°, 232.2 J · K−1 · mol−1