Na2SeO3 🔥→ Na2O + SeO2
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- Decomposition of sodium selenite
Decomposition of sodium selenite yields sodium oxide and selenium dioxide (Other reactions are here). This reaction is an acid-base reaction and is classified as follows:
- Thermal decomposition without redox
- Thermal decomposition of oxoacid salt without redox
- Thermal decomposition of salt of oxoacid and hydroxide base
Table of contents
Reaction data
Chemical equation
- Decomposition of sodium selenite
General equation
- Thermal decomposition without redox
- Thermally decomposable substanceLewis conjugate🔥⟶ ProductLewis acid + ProductLewis base
- Thermal decomposition of oxoacid salt without redox
- Oxoacid saltLewis conjugate🔥⟶ Basic oxideLewis base + Acidic oxideLewis acid + (H2O)
- Thermal decomposition of salt of oxoacid and hydroxide base
- Salt of oxoacid and hydroxide baseLewis conjugate🔥⟶ Basic oxideLewis base + Acidic oxideLewis acid
Oxidation state of each atom
- Decomposition of sodium selenite
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| Na2SeO3 | Sodium selenite | 1 | Lewis conjugate | Thermally decomposable Oxoacid salt Salt of oxoacid and hydroxide base |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| Na2O | Sodium oxide | 1 | Lewis acid Lewis base | – Basic oxide |
| SeO2 | Selenium dioxide | 1 | Lewis acid | – Acidic oxide |
Thermodynamic changes
Changes in standard condition
- Decomposition of sodium selenite
| 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 | 319.0 | – | – | – |
per 1 mol of | 319.0 | – | – | – |
per 1 mol of | 319.0 | – | – | – |
per 1 mol of | 319.0 | – | – | – |
Changes in aqueous solution
- Decomposition of sodium selenite
| 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 | 353.7 | – | – | – |
per 1 mol of | 353.7 | – | – | – |
per 1 mol of | 353.7 | – | – | – |
per 1 mol of | 353.7 | – | – | – |
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 |
|---|---|---|---|---|
| Na2SeO3 (cr) | -958.6[1] | – | – | – |
| Na2SeO3 (ai) | -989.5[1] | -893.7[1] | 130[1] | – |
| Na2SeO3 (cr) 5 hydrate | -2404.13[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 |
|---|---|---|---|---|
| Na2O (cr) | -414.22[1] | -375.46[1] | 75.06[1] | 69.12[1] |
| Na2O (g) | -35.6[1] | -52.3[1] | 261.2[1] | 55.2[1] |
| SeO2 (cr) | -225.35[1] | – | – | – |
| SeO2 (aq) | -221.63[1] | – | – | – |
* (cr):Crystalline solid, (g):Gas, (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°, -958.6 kJ · mol−1
- ^ ΔfH°, -989.5 kJ · mol−1
- ^ ΔfG°, -893.7 kJ · mol−1
- ^ S°, 130. J · K−1 · mol−1
- ^ ΔfH°, -2404.13 kJ · mol−1
- ^ ΔfH°, -414.22 kJ · mol−1
- ^ ΔfG°, -375.46 kJ · mol−1
- ^ S°, 75.06 J · K−1 · mol−1
- ^ Cp°, 69.12 J · K−1 · mol−1
- ^ ΔfH°, -35.6 kJ · mol−1
- ^ ΔfG°, -52.3 kJ · mol−1
- ^ S°, 261.2 J · K−1 · mol−1
- ^ Cp°, 55.2 J · K−1 · mol−1
- ^ ΔfH°, -225.35 kJ · mol−1
- ^ ΔfH°, -221.63 kJ · mol−1