(NH4)2Cr2O7 🔥→ N2O3↑ + 2Cr + 4H2O
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- Decomposition of ammonium dichromate
Decomposition of ammonium dichromate yields dinitrogen trioxide, , 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 dichromate
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 dichromate
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| (NH4)2Cr2O7 | Ammonium dichromate | 1 | Self redox agent | Thermally decomposable Oxoacid salt |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| N2O3 | Dinitrogen trioxide | 1 | Oxidized | – |
| 2 | Reduced | – | ||
| H2O | Water | 4 | – | – |
Thermodynamic changes
Changes in standard condition
- Decomposition of ammonium dichromate
| 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 | 747.1 | – | – | – |
per 1 mol of | 747.1 | – | – | – |
per 1 mol of | 747.1 | – | – | – |
| 373.6 | – | – | – | |
per 1 mol of | 186.8 | – | – | – |
Changes in aqueous solution
- Decomposition of ammonium dichromate◆
ΔrG 650.4 kJ/mol K 0.11 × 10−113 pK 113.95
| 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 | 695.6 | 650.4 | 150.8 | – |
per 1 mol of | 695.6 | 650.4 | 150.8 | – |
per 1 mol of | 695.6 | 650.4 | 150.8 | – |
| 347.8 | 325.2 | 75.40 | – | |
per 1 mol of | 173.9 | 162.6 | 37.70 | – |
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)2Cr2O7 (cr) | -1806.7[1] | – | – | – |
| (NH4)2Cr2O7 (ai) | -1755.2[1] | -1459.5[1] | 488.7[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 |
|---|---|---|---|---|
| N2O3 (l) | 50.29[1] | – | – | – |
| N2O3 (g) | 83.72[1] | 139.46[1] | 312.28[1] | 65.61[1] |
| (cr) | 0[1] | 0[1] | 23.77[1] | 23.35[1] |
| (g) | 396.6[1] | 351.8[1] | 174.50[1] | 20.79[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] |
* (l):Liquid, (g):Gas, (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°, -1806.7 kJ · mol−1
- ^ ΔfH°, -1755.2 kJ · mol−1
- ^ ΔfG°, -1459.5 kJ · mol−1
- ^ S°, 488.7 J · K−1 · mol−1
- ^ ΔfH°, 50.29 kJ · mol−1
- ^ ΔfH°, 83.72 kJ · mol−1
- ^ ΔfG°, 139.46 kJ · mol−1
- ^ S°, 312.28 J · K−1 · mol−1
- ^ Cp°, 65.61 J · K−1 · mol−1
- ^ ΔfH°, 0 kJ · mol−1
- ^ ΔfG°, 0 kJ · mol−1
- ^ S°, 23.77 J · K−1 · mol−1
- ^ Cp°, 23.35 J · K−1 · mol−1
- ^ ΔfH°, 396.6 kJ · mol−1
- ^ ΔfG°, 351.8 kJ · mol−1
- ^ S°, 174.50 J · K−1 · mol−1
- ^ Cp°, 20.79 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