7(NH4)2Cr2O7 + 6e− → 7(NH4)2CrO4 + Cr + 3Cr2O72−
Last updated:
- Reduction of ammonium dichromate
- 7(NH4)2Cr2O7Ammonium dichromate + 6e−Electron7(NH4)2CrO4Ammonium chromate + + 3Cr2O72−Dichromate ion⟶
Reduction of ammonium dichromate yields ammonium chromate, , and dichromate 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
- 7(NH4)2Cr2O7Ammonium dichromate + 6e−Electron7(NH4)2CrO4Ammonium chromate + + 3Cr2O72−Dichromate 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 | 7 | Oxidizing | – |
e− | Electron | 6 | – | Electron |
Products
Chemical formula | Name | Coefficient | Type | Type in general equation |
---|---|---|---|---|
(NH4)2CrO4 | Ammonium chromate | 7 | – | – |
1 | Reduced | – | ||
Cr2O72− | Dichromate ion | 3 | – | – |
Thermodynamic changes
Changes in standard condition
- Reduction of ammonium dichromate◆
ΔrG 108.7 kJ/mol K 0.90 × 10−19 pK 19.04 - 7(NH4)2Cr2O7Ionized aqueous solution + 6e−7(NH4)2CrO4Ionized aqueous solution + Crystalline solid + 3Cr2O72−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 | −207.6 | 108.7 | −672.4 | – |
per 1 mol of | −29.66 | 15.53 | −96.06 | – |
per 1 mol of Electron | −34.60 | 18.12 | −112.1 | – |
per 1 mol of | −29.66 | 15.53 | −96.06 | – |
−207.6 | 108.7 | −672.4 | – | |
per 1 mol of Dichromate ion | −69.20 | 36.23 | −224.1 | – |
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] | – |
(cr) | 0[1] | 0[1] | 23.77[1] | 23.35[1] |
(g) | 396.6[1] | 351.8[1] | 174.50[1] | 20.79[1] |
Cr2O72− (ao) | -1490.3[1] | -1301.1[1] | 261.9[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°, 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°, -1490.3 kJ · mol−1
- ^ ΔfG°, -1301.1 kJ · mol−1
- ^ S°, 261.9 J · K−1 · mol−1