8KI + CaCr2O7 → 4K2O + 3I2 + Cr2O3 + CaI2
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The reaction of potassium iodide and calcium dichromate yields potassium oxide, , chromium(III) oxide, and calcium iodide (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 calcium 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 calcium dichromate
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| KI | Potassium iodide | 8 | Reducing | Oxidizable |
| CaCr2O7 | Calcium dichromate | 1 | Oxidizing | Oxidizing |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| K2O | Potassium oxide | 4 | – | – |
| 3 | Oxidized | – | ||
| Cr2O3 | Chromium(III) oxide | 1 | Reduced | – |
| CaI2 | Calcium iodide | 1 | – | – |
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 |
|---|---|---|---|---|
| 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] |
| CaCr2O7 | – | – | – | – |
* (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 |
|---|---|---|---|---|
| K2O (cr) | -361.5[1] | -322.1[2] | 94.1[2] | 83.7[2] |
| K2O (g) | -63[1] | – | – | – |
| (cr) | 0[1] | 0[1] | 116.135[1] | 54.438[1] |
| (g) | 62.438[1] | 19.327[1] | 260.69[1] | 36.90[1] |
| (ao) | 22.6[1] | 16.40[1] | 137.2[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] | – | – | – |
| CaI2 (cr) | -533.5[1] | -528.9[1] | 142[1] | – |
| CaI2 (g) | -272[1] | – | – | – |
| CaI2 (ai) | -653.21[1] | -656.72[1] | 169.5[1] | – |
| CaI2 (cr) 8 hydrate | -2929.6[1] | – | – | – |
* (cr):Crystalline solid, (g):Gas, (ao):Un-ionized aqueous solution, (ai):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°, -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°, -361.5 kJ · mol−1
- ^ ΔfH°, -63. kJ · mol−1
- ^ ΔfH°, 0 kJ · mol−1
- ^ ΔfG°, 0 kJ · mol−1
- ^ S°, 116.135 J · K−1 · mol−1
- ^ Cp°, 54.438 J · K−1 · mol−1
- ^ ΔfH°, 62.438 kJ · mol−1
- ^ ΔfG°, 19.327 kJ · mol−1
- ^ S°, 260.69 J · K−1 · mol−1
- ^ Cp°, 36.90 J · K−1 · mol−1
- ^ ΔfH°, 22.6 kJ · mol−1
- ^ ΔfG°, 16.40 kJ · mol−1
- ^ S°, 137.2 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°, -533.5 kJ · mol−1
- ^ ΔfG°, -528.9 kJ · mol−1
- ^ S°, 142. J · K−1 · mol−1
- ^ ΔfH°, -272. kJ · mol−1
- ^ ΔfH°, -653.21 kJ · mol−1
- ^ ΔfG°, -656.72 kJ · mol−1
- ^ S°, 169.5 J · K−1 · mol−1
- ^ ΔfH°, -2929.6 kJ · mol−1
- 2James G. Speight (2017)Lange's Handbook of Chemistry, 17th editionMcGraw Hill Education
- ^ ΔfG°, -322.1 kJ · mol−1 - p.280
- ^ S°, 94.1 J · K−1 · mol−1 - p.280
- ^ Cp°, 83.7 J · K−1 · mol−1 - p.280