3(NH4)2Cr2O7 🔥→ 3N2O5 + 6Cr + 12H2↑ + 2O3↑
Last updated:
- Decomposition of ammonium dichromate
Decomposition of ammonium dichromate yields dinitrogen pentaoxide, , , 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 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 | 3 | Self redox agent | Thermally decomposable Oxoacid salt |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| N2O5 | Dinitrogen pentaoxide | 3 | Oxidized | – |
| 6 | Reduced | – | ||
| 12 | Reduced | – | ||
| 2 | Oxidized | – |
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 | 5576.2 | – | – | – |
per 1 mol of | 1858.7 | – | – | – |
per 1 mol of | 1858.7 | – | – | – |
| 929.37 | – | – | – | |
| 464.68 | – | – | – | |
| 2788.1 | – | – | – |
Changes in aqueous solution (1)
- Decomposition of ammonium dichromate◆
ΔrG 5046.6 kJ/mol K 0.75 × 10−884 pK 884.13
| 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 | 5421.7 | 5046.6 | 1257.2 | – |
per 1 mol of | 1807.2 | 1682.2 | 419.07 | – |
per 1 mol of | 1807.2 | 1682.2 | 419.07 | – |
| 903.62 | 841.10 | 209.53 | – | |
| 451.81 | 420.55 | 104.77 | – | |
| 2710.8 | 2523.3 | 628.60 | – |
Changes in aqueous solution (2)
- Decomposition of ammonium dichromate◆
ΔrG 5068.4 kJ/mol K 0.11 × 10−887 pK 887.95 - 3(NH4)2Cr2O7Ionized aqueous solution3N2O5Crystalline solid + 6Crystalline solid + 12↑Gas + 2↑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 | 5388.1 | 5068.4 | 1071 | – |
per 1 mol of | 1796.0 | 1689.5 | 357.0 | – |
per 1 mol of | 1796.0 | 1689.5 | 357.0 | – |
| 898.02 | 844.73 | 178.5 | – | |
| 449.01 | 422.37 | 89.25 | – | |
| 2694.1 | 2534.2 | 535.5 | – |
Changes in aqueous solution (3)
- Decomposition of ammonium dichromate◆
ΔrG 5257.8 kJ/mol K 0.75 × 10−921 pK 921.13 - 3(NH4)2Cr2O7Ionized aqueous solution3N2O5Crystalline solid + 6Crystalline solid + 12↑Un-ionized aqueous solution + 2↑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 | 5371.3 | 5257.8 | 6613 | – |
per 1 mol of | 1790.4 | 1752.6 | 2204 | – |
per 1 mol of | 1790.4 | 1752.6 | 2204 | – |
| 895.22 | 876.30 | 1102 | – | |
| 447.61 | 438.15 | 551.1 | – | |
| 2685.7 | 2628.9 | 3307 | – |
Changes in aqueous solution (4)
- Decomposition of ammonium dichromate◆
ΔrG 5279.6 kJ/mol K 0.11 × 10−924 pK 924.95 - 3(NH4)2Cr2O7Ionized aqueous solution3N2O5Crystalline solid + 6Crystalline solid + 12↑Un-ionized aqueous solution + 2↑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 | 5337.7 | 5279.6 | 6427 | – |
per 1 mol of | 1779.2 | 1759.9 | 2142 | – |
per 1 mol of | 1779.2 | 1759.9 | 2142 | – |
| 889.62 | 879.93 | 1071 | – | |
| 444.81 | 439.97 | 535.6 | – | |
| 2668.8 | 2639.8 | 3214 | – |
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 |
|---|---|---|---|---|
| N2O5 (cr) | -43.1[1] | 113.9[1] | 178.2[1] | 143.1[1] |
| N2O5 (g) | 11.3[1] | 115.1[1] | 355.7[1] | 84.5[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] |
| (g) | 0[1] | 0[1] | 130.684[1] | 28.824[1] |
| (ao) | -4.2[1] | 17.6[1] | 577[1] | – |
| (g) | 142.7[1] | 163.2[1] | 238.93[1] | 39.20[1] |
| (ao) | 125.9[1] | 174.1[1] | 146[1] | – |
* (cr):Crystalline solid, (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°, -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°, -43.1 kJ · mol−1
- ^ ΔfG°, 113.9 kJ · mol−1
- ^ S°, 178.2 J · K−1 · mol−1
- ^ Cp°, 143.1 J · K−1 · mol−1
- ^ ΔfH°, 11.3 kJ · mol−1
- ^ ΔfG°, 115.1 kJ · mol−1
- ^ S°, 355.7 J · K−1 · mol−1
- ^ Cp°, 84.5 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°, 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
- ^ ΔfH°, 142.7 kJ · mol−1
- ^ ΔfG°, 163.2 kJ · mol−1
- ^ S°, 238.93 J · K−1 · mol−1
- ^ Cp°, 39.20 J · K−1 · mol−1
- ^ ΔfH°, 125.9 kJ · mol−1
- ^ ΔfG°, 174.1 kJ · mol−1
- ^ S°, 146. J · K−1 · mol−1