KI + (NH4)2Cr2O7 🔥→ KIO3 + Cr2O3 + 2NH3↑ + H2O
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The reaction of potassium iodide and ammonium dichromate yields potassium iodate, chromium(III) oxide, ammonia, 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
- Reaction of potassium iodide and ammonium dichromate
General equation
- Reaction of oxidizable species and oxidizing species
- Oxidizable speciesReducing agent + Oxidizing speciesOxidizing agent ⟶ ProductOxidation product + ProductReduction product
Oxidation state of each atom
- Reaction of potassium iodide and ammonium dichromate
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| KI | Potassium iodide | 1 | Reducing | Oxidizable |
| (NH4)2Cr2O7 | Ammonium dichromate | 1 | Oxidizing | Oxidizing |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| KIO3 | Potassium iodate | 1 | Oxidized | – |
| Cr2O3 | Chromium(III) oxide | 1 | Reduced | – |
| NH3 | Ammonia | 2 | – | – |
| H2O | Water | 1 | – | – |
Thermodynamic changes
Changes in standard condition
- Reaction of potassium iodide and 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 | 115.5 | – | – | – |
per 1 mol of | 115.5 | – | – | – |
per 1 mol of | 115.5 | – | – | – |
per 1 mol of | 115.5 | – | – | – |
per 1 mol of | 115.5 | – | – | – |
per 1 mol of | 57.75 | – | – | – |
per 1 mol of | 115.5 | – | – | – |
Changes in aqueous solution (1)
- Reaction of potassium iodide and ammonium dichromate◆
ΔrG 55.0 kJ/mol K 0.23 × 10−9 pK 9.64
| 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 | 71.4 | 55.0 | 54.4 | – |
per 1 mol of | 71.4 | 55.0 | 54.4 | – |
per 1 mol of | 71.4 | 55.0 | 54.4 | – |
per 1 mol of | 71.4 | 55.0 | 54.4 | – |
per 1 mol of | 71.4 | 55.0 | 54.4 | – |
per 1 mol of | 35.7 | 27.5 | 27.2 | – |
per 1 mol of | 71.4 | 55.0 | 54.4 | – |
Changes in aqueous solution (2)
- Reaction of potassium iodide and ammonium dichromate◆
ΔrG 34.9 kJ/mol K 0.77 × 10−6 pK 6.11
| 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 | 3.1 | 34.9 | −107.9 | – |
per 1 mol of | 3.1 | 34.9 | −107.9 | – |
per 1 mol of | 3.1 | 34.9 | −107.9 | – |
per 1 mol of | 3.1 | 34.9 | −107.9 | – |
per 1 mol of | 3.1 | 34.9 | −107.9 | – |
per 1 mol of | 1.6 | 17.4 | −53.95 | – |
per 1 mol of | 3.1 | 34.9 | −107.9 | – |
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 |
|---|---|---|---|---|
| KI (cr) | -327.900[1] | -324.892[1] | 106.32[1] | 52.93[1] |
| KI (g) | -125.5[1] | -166.1[1] | 258.3[1] | 37.11[1] |
| KI (ai) | -307.57[1] | -334.85[1] | 213.8[1] | -120.5[1] |
| (NH4)2Cr2O7 (cr) | -1806.7[1] | – | – | – |
| (NH4)2Cr2O7 (ai) | -1755.2[1] | -1459.5[1] | 488.7[1] | – |
* (cr):Crystalline solid, (g):Gas, (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 |
|---|---|---|---|---|
| KIO3 (cr) | -501.37[1] | -418.35[1] | 151.46[1] | 106.48[1] |
| KIO3 (ai) | -473.6[1] | -411.2[1] | 220.9[1] | – |
| Cr2O3 (cr) | -1139.7[1] | -1058.1[1] | 81.2[1] | 118.74[1] |
| Cr2O3 (cr) 1 hydrate | -1506[1] | – | – | – |
| Cr2O3 (cr) 2 hydrate | -1845[1] | – | – | – |
| Cr2O3 (cr) 3 hydrate | -2171[1] | – | – | – |
| NH3 (g) | -46.11[1] | -16.45[1] | 192.45[1] | 35.06[1] |
| NH3 (ao) | -80.29[1] | -26.50[1] | 111.3[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] |
* (cr):Crystalline solid, (ai):Ionized aqueous solution, (g):Gas, (ao):Un-ionized aqueous solution, (l):Liquid
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°, -327.900 kJ · mol−1
- ^ ΔfG°, -324.892 kJ · mol−1
- ^ S°, 106.32 J · K−1 · mol−1
- ^ Cp°, 52.93 J · K−1 · mol−1
- ^ ΔfH°, -125.5 kJ · mol−1
- ^ ΔfG°, -166.1 kJ · mol−1
- ^ S°, 258.3 J · K−1 · mol−1
- ^ Cp°, 37.11 J · K−1 · mol−1
- ^ ΔfH°, -307.57 kJ · mol−1
- ^ ΔfG°, -334.85 kJ · mol−1
- ^ S°, 213.8 J · K−1 · mol−1
- ^ Cp°, -120.5 J · K−1 · mol−1
- ^ 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°, -501.37 kJ · mol−1
- ^ ΔfG°, -418.35 kJ · mol−1
- ^ S°, 151.46 J · K−1 · mol−1
- ^ Cp°, 106.48 J · K−1 · mol−1
- ^ ΔfH°, -473.6 kJ · mol−1
- ^ ΔfG°, -411.2 kJ · mol−1
- ^ S°, 220.9 J · K−1 · mol−1
- ^ ΔfH°, -1139.7 kJ · mol−1
- ^ ΔfG°, -1058.1 kJ · mol−1
- ^ S°, 81.2 J · K−1 · mol−1
- ^ Cp°, 118.74 J · K−1 · mol−1
- ^ ΔfH°, -1506. kJ · mol−1
- ^ ΔfH°, -1845. kJ · mol−1
- ^ ΔfH°, -2171. kJ · mol−1
- ^ ΔfH°, -46.11 kJ · mol−1
- ^ ΔfG°, -16.45 kJ · mol−1
- ^ S°, 192.45 J · K−1 · mol−1
- ^ Cp°, 35.06 J · K−1 · mol−1
- ^ ΔfH°, -80.29 kJ · mol−1
- ^ ΔfG°, -26.50 kJ · mol−1
- ^ S°, 111.3 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