2(NH4)3AsO4 🔥→ 3N2H4 + 2H3AsO4 + 3H2↑
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- Decomposition of ammonium arsenate
Decomposition of ammonium arsenate yields hydrazine, arsenic 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 arsenate
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 arsenate
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| (NH4)3AsO4 | Ammonium arsenate | 2 | Self redox agent | Thermally decomposable Oxoacid salt |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| N2H4 | Hydrazine | 3 | Oxidized | – |
| H3AsO4 | Arsenic acid | 2 | – | – |
| 3 | Reduced | – |
Thermodynamic changes
Changes in standard condition
- Decomposition of ammonium arsenate
| 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 | 911.7 | – | – | – |
per 1 mol of | 455.9 | – | – | – |
per 1 mol of | 303.9 | – | – | – |
per 1 mol of | 455.9 | – | – | – |
| 303.9 | – | – | – |
Changes in aqueous solution (1)
- Decomposition of ammonium arsenate◆
ΔrG 624.9 kJ/mol K 0.33 × 10−109 pK 109.48 - 2(NH4)3AsO4Ionized aqueous solution3N2H4Un-ionized aqueous solution + 2H3AsO4Un-ionized aqueous solution + 3↑Gas🔥⟶
| 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 | 869.3 | 624.9 | 819 | – |
per 1 mol of | 434.6 | 312.4 | 410 | – |
per 1 mol of | 289.8 | 208.3 | 273 | – |
per 1 mol of | 434.6 | 312.4 | 410 | – |
| 289.8 | 208.3 | 273 | – |
Changes in aqueous solution (2)
- Decomposition of ammonium arsenate◆
ΔrG 677.7 kJ/mol K 0.19 × 10−118 pK 118.73 - 2(NH4)3AsO4Ionized aqueous solution3N2H4Un-ionized aqueous solution + 2H3AsO4Un-ionized aqueous solution + 3↑Un-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 | 856.7 | 677.7 | 2158 | – |
per 1 mol of | 428.4 | 338.9 | 1079 | – |
per 1 mol of | 285.6 | 225.9 | 719.3 | – |
per 1 mol of | 428.4 | 338.9 | 1079 | – |
| 285.6 | 225.9 | 719.3 | – |
Changes in aqueous solution (3)
- Decomposition of ammonium arsenate
- 2(NH4)3AsO4Ionized aqueous solution3N2H4Un-ionized aqueous solution + 2H3AsO4Aqueous solution + 3↑Gas🔥⟶
| 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 | 865.1 | – | – | – |
per 1 mol of | 432.6 | – | – | – |
per 1 mol of | 288.4 | – | – | – |
per 1 mol of | 432.6 | – | – | – |
| 288.4 | – | – | – |
Changes in aqueous solution (4)
- Decomposition of ammonium arsenate
- 2(NH4)3AsO4Ionized aqueous solution3N2H4Un-ionized aqueous solution + 2H3AsO4Aqueous solution + 3↑Un-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 | 852.5 | – | – | – |
per 1 mol of | 426.3 | – | – | – |
per 1 mol of | 284.2 | – | – | – |
per 1 mol of | 426.3 | – | – | – |
| 284.2 | – | – | – |
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)3AsO4 (cr) | -1286.2[1] | – | – | – |
| (NH4)3AsO4 (ai) | -1285.66[1] | -886.32[1] | 177.4[1] | – |
| (NH4)3AsO4 (cr) 3 hydrate | -2166.9[1] | – | – | – |
* (cr):Crystalline solid, (ai):Ionized 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] | – |
| H3AsO4 (cr) | -906.3[1] | – | – | – |
| H3AsO4 (ao) | -902.5[1] | -766.0[1] | 184[1] | – |
| H3AsO4 (aq) | -904.6[1] | – | – | – |
| (g) | 0[1] | 0[1] | 130.684[1] | 28.824[1] |
| (ao) | -4.2[1] | 17.6[1] | 577[1] | – |
* (l):Liquid, (g):Gas, (ao):Un-ionized aqueous solution, (cr):Crystalline solid, (aq):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°, -1286.2 kJ · mol−1
- ^ ΔfH°, -1285.66 kJ · mol−1
- ^ ΔfG°, -886.32 kJ · mol−1
- ^ S°, 177.4 J · K−1 · mol−1
- ^ ΔfH°, -2166.9 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°, -906.3 kJ · mol−1
- ^ ΔfH°, -902.5 kJ · mol−1
- ^ ΔfG°, -766.0 kJ · mol−1
- ^ S°, 184. J · K−1 · mol−1
- ^ ΔfH°, -904.6 kJ · mol−1
- ^ ΔfH°, 0 kJ · mol−1
- ^ ΔfG°, 0 kJ · mol−1
- ^ S°, 130.684 J · K−1 · mol−1
- ^ Cp°, 28.824 J · K−1 · mol−1
- ^ ΔfH°, -4.2 kJ · mol−1
- ^ ΔfG°, 17.6 kJ · mol−1
- ^ S°, 577 J · K−1 · mol−1