4(NH4)2Cr2O7 + 3e− → 4(NH4)2CrO4 + Cr3+ + 3CrO42−
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- Reduction of ammonium dichromate
- 4(NH4)2Cr2O7Ammonium dichromate + 3e−Electron4(NH4)2CrO4Ammonium chromate + Cr3+Chromium(III) ion + 3CrO42−Chromate ion⟶
Reduction of ammonium dichromate yields ammonium chromate, chromium(III) ion, and chromate ion (Other reactions are here). This reaction is an oxidation-reduction reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Reduction of ammonium dichromate
- 4(NH4)2Cr2O7Ammonium dichromate + 3e−Electron4(NH4)2CrO4Ammonium chromate + Cr3+Chromium(III) ion + 3CrO42−Chromate ion⟶
General equation
- Reduction of reducible species
- ReactantOxidizing agent + e− ⟶ ProductReduction product
Oxidation state of each atom
- Reduction of ammonium dichromate
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| (NH4)2Cr2O7 | Ammonium dichromate | 4 | Oxidizing | – |
| e− | Electron | 3 | – | Electron |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| (NH4)2CrO4 | Ammonium chromate | 4 | – | – |
| Cr3+ | Chromium(III) ion | 1 | Reduced | – |
| CrO42− | Chromate ion | 3 | – | – |
Thermodynamic changes
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] | – |
| e− | – | – | – | – |
* (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 |
|---|---|---|---|---|
| (NH4)2CrO4 (cr) | -1167.3[1] | – | – | – |
| (NH4)2CrO4 (ai) | -1146.16[1] | -886.36[1] | 277.0[1] | – |
| Cr3+ (g) | 5648.4[1] | – | – | – |
| CrO42− (ao) | -881.15[1] | -727.75[1] | 50.21[1] | – |
* (cr):Crystalline solid, (ai):Ionized aqueous solution, (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°, -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°, 5648.4 kJ · mol−1
- ^ ΔfH°, -881.15 kJ · mol−1
- ^ ΔfG°, -727.75 kJ · mol−1
- ^ S°, 50.21 J · K−1 · mol−1