6K2Cr2O7 + 2(NH4)3AsO4 💧→ 6K2CrO4↓ + 3(NH4)2Cr2O7 + As2O5
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The reaction of potassium dichromate and ammonium arsenate yields potassium chromate, ammonium dichromate, and diarsenic pentaoxide (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 potassium dichromate and ammonium arsenate
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 potassium dichromate and ammonium arsenate
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| K2Cr2O7 | Potassium dichromate | 6 | Lewis acid | Soluble in water |
| (NH4)3AsO4 | Ammonium arsenate | 2 | Lewis base | Soluble in water |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| K2CrO4 | Potassium chromate | 6 | Lewis conjugate | Insoluble in water |
| (NH4)2Cr2O7 | Ammonium dichromate | 3 | Non-redox product | – |
| As2O5 | Diarsenic pentaoxide | 1 | Non-redox product | – |
Thermodynamic changes
Changes in standard condition
- Reaction of potassium dichromate and ammonium arsenate
- 6K2Cr2O7Crystalline solid + 2(NH4)3AsO4Crystalline solid6K2CrO4↓Crystalline solid + 3(NH4)2Cr2O7Crystalline solid + As2O5Crystalline solid💧⟶
| 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 | 174.2 | – | – | – |
per 1 mol of | 29.03 | – | – | – |
per 1 mol of | 87.10 | – | – | – |
per 1 mol of | 29.03 | – | – | – |
per 1 mol of | 58.07 | – | – | – |
per 1 mol of | 174.2 | – | – | – |
Changes in aqueous solution
- Reaction of potassium dichromate and ammonium arsenate
- 6K2Cr2O7Ionized aqueous solution + 2(NH4)3AsO4Ionized aqueous solution6K2CrO4↓Ionized aqueous solution + 3(NH4)2Cr2O7Ionized aqueous solution + As2O5Aqueous 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 | 8.3 | – | – | – |
per 1 mol of | 1.4 | – | – | – |
per 1 mol of | 4.2 | – | – | – |
per 1 mol of | 1.4 | – | – | – |
per 1 mol of | 2.8 | – | – | – |
per 1 mol of | 8.3 | – | – | – |
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 |
|---|---|---|---|---|
| K2Cr2O7 (cr) | -2061.5[1] | -1881.8[1] | 291.2[1] | 219.24[1] |
| K2Cr2O7 (ai) | -1994.9[1] | -1867.6[1] | 466.9[1] | – |
| (NH4)3AsO4 (cr) | -1286.2[1] | – | – | – |
| (NH4)3AsO4 (ai) | -1285.66[1] | -886.32[1] | 177.4[1] | – |
| (NH4)3AsO4 (cr) 3 hydrate | -2166.9[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 |
|---|---|---|---|---|
| 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] | – |
| (NH4)2Cr2O7 (cr) | -1806.7[1] | – | – | – |
| (NH4)2Cr2O7 (ai) | -1755.2[1] | -1459.5[1] | 488.7[1] | – |
| As2O5 (cr) | -924.87[1] | -782.3[1] | 105.4[1] | 116.52[1] |
| As2O5 (aq) | -951.4[1] | – | – | – |
| As2O5 (cr) 4 hydrate | -2104.6[1] | – | – | – |
* (cr):Crystalline solid, (ai):Ionized aqueous solution, (aq):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°, -2061.5 kJ · mol−1
- ^ ΔfG°, -1881.8 kJ · mol−1
- ^ S°, 291.2 J · K−1 · mol−1
- ^ Cp°, 219.24 J · K−1 · mol−1
- ^ ΔfH°, -1994.9 kJ · mol−1
- ^ ΔfG°, -1867.6 kJ · mol−1
- ^ S°, 466.9 J · K−1 · mol−1
- ^ ΔfH°, -1286.2 kJ · mol−1
- ^ ΔfH°, -1285.66 kJ · mol−1
- ^ ΔfG°, -886.32 kJ · mol−1
- ^ S°, 177.4 J · K−1 · mol−1
- ^ ΔfH°, -2166.9 kJ · 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°, -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°, -924.87 kJ · mol−1
- ^ ΔfG°, -782.3 kJ · mol−1
- ^ S°, 105.4 J · K−1 · mol−1
- ^ Cp°, 116.52 J · K−1 · mol−1
- ^ ΔfH°, -951.4 kJ · mol−1
- ^ ΔfH°, -2104.6 kJ · mol−1