4K3AsO4 🔥→ 6K2O + 4As + 5O2↑
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- Decomposition of potassium arsenate
Decomposition of potassium arsenate yields potassium oxide, , and (Other reactions are here). This reaction is an oxidation-reduction reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Decomposition of potassium arsenate
General equation
- Thermal decomposition with redox
- Thermally decomposable substanceSelf redox agent🔥⟶ ProductOxidation product + ProductReduction product
- Thermal decomposition of oxoacid salt with redox
- Oxoacid saltSelf redox agent🔥⟶ ProductOxidation product + ProductReduction product
Oxidation state of each atom
- Decomposition of potassium arsenate
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| K3AsO4 | Potassium arsenate | 4 | Self redox agent | Thermally decomposable Oxoacid salt |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| K2O | Potassium oxide | 6 | – | – |
| 4 | Reduced | – | ||
| 5 | Oxidized | – |
Thermodynamic changes
Changes in aqueous solution (1)
- Decomposition of potassium arsenate◆
ΔrG 4060.3 kJ/mol K 0.46 × 10−711 pK 711.33
| 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 | 4412.1 | 4060.3 | 1151.5 | – |
per 1 mol of | 1103.0 | 1015.1 | 287.88 | – |
per 1 mol of | 735.35 | 676.72 | 191.92 | – |
| 1103.0 | 1015.1 | 287.88 | – | |
| 882.42 | 812.06 | 230.30 | – |
Changes in aqueous solution (2)
- Decomposition of potassium arsenate◆
ΔrG 4142.3 kJ/mol K 0.20 × 10−725 pK 725.70
| 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 | 4353.6 | 4142.3 | 680.3 | – |
per 1 mol of | 1088.4 | 1035.6 | 170.1 | – |
per 1 mol of | 725.60 | 690.38 | 113.4 | – |
| 1088.4 | 1035.6 | 170.1 | – | |
| 870.72 | 828.46 | 136.1 | – |
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 |
|---|---|---|---|---|
| K3AsO4 (ai) | -1645.27[1] | -1498.23[1] | 144.8[1] | – |
* (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) α, gray, metallic | 0[1] | 0[1] | 35.1[1] | 24.64[1] |
| (cr) γ, yellow, cubic | 14.6[1] | – | – | – |
| (am) β | 4.2[1] | – | – | – |
| (g) | 302.5[1] | 261.0[1] | 174.21[1] | 20.786[1] |
| (g) | 0[1] | 0[1] | 205.138[1] | 29.355[1] |
| (ao) | -11.7[1] | 16.4[1] | 110.9[1] | – |
* (cr):Crystalline solid, (g):Gas, (am):Amorphous solid, (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°, -1645.27 kJ · mol−1
- ^ ΔfG°, -1498.23 kJ · mol−1
- ^ S°, 144.8 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°, 35.1 J · K−1 · mol−1
- ^ Cp°, 24.64 J · K−1 · mol−1
- ^ ΔfH°, 14.6 kJ · mol−1
- ^ ΔfH°, 4.2 kJ · mol−1
- ^ ΔfH°, 302.5 kJ · mol−1
- ^ ΔfG°, 261.0 kJ · mol−1
- ^ S°, 174.21 J · K−1 · mol−1
- ^ Cp°, 20.786 J · K−1 · mol−1
- ^ ΔfH°, 0 kJ · mol−1
- ^ ΔfG°, 0 kJ · mol−1
- ^ S°, 205.138 J · K−1 · mol−1
- ^ Cp°, 29.355 J · K−1 · mol−1
- ^ ΔfH°, -11.7 kJ · mol−1
- ^ ΔfG°, 16.4 kJ · mol−1
- ^ S°, 110.9 J · K−1 · 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