2CaCr2O7 + 2KHS 💧→ 2CaS↓ + K2CrO4↓ + H2CrO4 + 2CrO3
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The reaction of calcium dichromate and potassium hydrogensulfide yields calcium sulfide, potassium chromate, chromic acid, and chromium(VI) oxide (Other reactions are here). This reaction is an acid-base reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Reaction of calcium dichromate and potassium hydrogensulfide
General equation
- Precipitation reaction
- Miscible with water/Very soluble in water/Soluble in waterLewis acid + Miscible with water/Very soluble in water/Soluble in waterLewis base💧⟶ Insoluble in water/Very slightly soluble in water/Slightly soluble in waterLewis conjugate + Product(Non-redox product)
Oxidation state of each atom
- Reaction of calcium dichromate and potassium hydrogensulfide
Reactants
Chemical formula | Name | Coefficient | Type | Type in general equation |
---|---|---|---|---|
CaCr2O7 | Calcium dichromate | 2 | Lewis acid | Very soluble in water |
KHS | Potassium hydrogensulfide | 2 | Lewis base | Soluble in water |
Products
Chemical formula | Name | Coefficient | Type | Type in general equation |
---|---|---|---|---|
CaS | Calcium sulfide | 2 | Lewis conjugate | Slightly soluble in water |
K2CrO4 | Potassium chromate | 1 | Lewis conjugate | Insoluble in water |
H2CrO4 | Chromic acid | 1 | Non-redox product | – |
CrO3 | Chromium(VI) oxide | 2 | Non-redox product | – |
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 |
---|---|---|---|---|
CaCr2O7 | – | – | – | – |
KHS (cr) | -265.10[1] | – | – | 75.31[1] |
KHS (ai) | -269.9[1] | -271.19[1] | 165.3[1] | – |
KHS (cr) 0.25 hydrate | -337.2[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 |
---|---|---|---|---|
CaS (cr) | -482.4[1] | -477.4[1] | 56.5[1] | 47.40[1] |
CaS (g) | – | – | – | – |
K2CrO4 (cr) | -1403.7[1] | -1295.7[1] | 200.12[1] | 145.98[1] |
K2CrO4 (ai) | -1385.91[1] | -1294.30[1] | 255.2[1] | – |
H2CrO4 | – | – | – | – |
CrO3 (cr) | -589.5[1] | – | – | – |
CrO3 (g) | -385.8[1] | – | – | – |
* (cr):Crystalline solid, (g):Gas, (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°, -265.10 kJ · mol−1
- ^ Cp°, 75.31 J · K−1 · mol−1
- ^ ΔfH°, -269.9 kJ · mol−1
- ^ ΔfG°, -271.19 kJ · mol−1
- ^ S°, 165.3 J · K−1 · mol−1
- ^ ΔfH°, -337.2 kJ · mol−1
- ^ ΔfH°, -482.4 kJ · mol−1
- ^ ΔfG°, -477.4 kJ · mol−1
- ^ S°, 56.5 J · K−1 · mol−1
- ^ Cp°, 47.40 J · K−1 · mol−1
- ^ ΔfH°, -1403.7 kJ · mol−1
- ^ ΔfG°, -1295.7 kJ · mol−1
- ^ S°, 200.12 J · K−1 · mol−1
- ^ Cp°, 145.98 J · K−1 · mol−1
- ^ ΔfH°, -1385.91 kJ · mol−1
- ^ ΔfG°, -1294.30 kJ · mol−1
- ^ S°, 255.2 J · K−1 · mol−1
- ^ ΔfH°, -589.5 kJ · mol−1
- ^ ΔfH°, -385.8 kJ · mol−1