2(NH4)2CrO4 🔥→ 2N2H4 + 2Cr(OH)3 + H2O2
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- Decomposition of ammonium chromate
Decomposition of ammonium chromate yields hydrazine, chromium(III) hydroxide, 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 chromate
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 chromate
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| (NH4)2CrO4 | Ammonium chromate | 2 | Self redox agent | Thermally decomposable Oxoacid salt |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| N2H4 | Hydrazine | 2 | Oxidized | – |
| Cr(OH)3 | Chromium(III) hydroxide | 2 | Reduced | – |
| 1 | Oxidized | – |
Thermodynamic changes
Changes in standard condition
- Decomposition of ammonium chromate
| 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 | 120.1 | – | – | – |
per 1 mol of | 60.05 | – | – | – |
per 1 mol of | 60.05 | – | – | – |
per 1 mol of | 60.05 | – | – | – |
| 120.1 | – | – | – |
Changes in aqueous solution
- Decomposition of ammonium chromate
- 2(NH4)2CrO4Ionized aqueous solution2N2H4Un-ionized aqueous solution + 2Cr(OH)3Crystalline solidprecipitated + 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 | 41.8 | – | – | – |
per 1 mol of | 20.9 | – | – | – |
per 1 mol of | 20.9 | – | – | – |
per 1 mol of | 20.9 | – | – | – |
| 41.8 | – | – | – |
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)2CrO4 (cr) | -1167.3[1] | – | – | – |
| (NH4)2CrO4 (ai) | -1146.16[1] | -886.36[1] | 277.0[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] | – |
| Cr(OH)3 (cr) precipitated | -1064.0[1] | – | – | – |
| (l) | -187.78[1] | -120.35[1] | 109.6[1] | 89.1[1] |
| (g) | -136.31[1] | -105.57[1] | 232.7[1] | 43.1[1] |
| (ao) | -191.17[1] | -134.03[1] | 143.9[1] | – |
* (l):Liquid, (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°, -1167.3 kJ · mol−1
- ^ ΔfH°, -1146.16 kJ · mol−1
- ^ ΔfG°, -886.36 kJ · mol−1
- ^ S°, 277.0 J · K−1 · 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°, -1064.0 kJ · mol−1
- ^ ΔfH°, -187.78 kJ · mol−1
- ^ ΔfG°, -120.35 kJ · mol−1
- ^ S°, 109.6 J · K−1 · mol−1
- ^ Cp°, 89.1 J · K−1 · mol−1
- ^ ΔfH°, -136.31 kJ · mol−1
- ^ ΔfG°, -105.57 kJ · mol−1
- ^ S°, 232.7 J · K−1 · mol−1
- ^ Cp°, 43.1 J · K−1 · mol−1
- ^ ΔfH°, -191.17 kJ · mol−1
- ^ ΔfG°, -134.03 kJ · mol−1
- ^ S°, 143.9 J · K−1 · mol−1