Na2SO3 🔥→ Na2O + SO2↑
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- Decomposition of sodium sulfite
Decomposition of sodium sulfite yields sodium oxide and sulfur 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 sulfite
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 sulfite
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| Na2SO3 | Sodium sulfite | 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 |
| SO2 | Sulfur dioxide | 1 | Lewis acid | – Acidic oxide |
Thermodynamic changes
Changes in standard condition
- Decomposition of sodium sulfite◆
ΔrG 336.8 kJ/mol K 0.99 × 10−59 pK 59.00
| 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 | 389.8 | 336.8 | 177.34 | −11.26 |
per 1 mol of | 389.8 | 336.8 | 177.34 | −11.26 |
per 1 mol of | 389.8 | 336.8 | 177.34 | −11.26 |
per 1 mol of | 389.8 | 336.8 | 177.34 | −11.26 |
Changes in aqueous solution (1)
- Decomposition of sodium sulfite◆
ΔrG 334.74 kJ/mol K 0.23 × 10−58 pK 58.64
| 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 | 404.82 | 334.74 | 235.4 | – |
per 1 mol of | 404.82 | 334.74 | 235.4 | – |
per 1 mol of | 404.82 | 334.74 | 235.4 | – |
per 1 mol of | 404.82 | 334.74 | 235.4 | – |
Changes in aqueous solution (2)
- Decomposition of sodium sulfite◆
ΔrG 334.25 kJ/mol K 0.28 × 10−58 pK 58.56
| 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 | 378.67 | 334.25 | 149.1 | – |
per 1 mol of | 378.67 | 334.25 | 149.1 | – |
per 1 mol of | 378.67 | 334.25 | 149.1 | – |
per 1 mol of | 378.67 | 334.25 | 149.1 | – |
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 |
|---|---|---|---|---|
| Na2SO3 (cr) | -1100.8[1] | -1012.5[1] | 145.94[1] | 120.25[1] |
| Na2SO3 (ai) | -1115.87[1] | -1010.39[1] | 87.9[1] | – |
| Na2SO3 (cr) 7 hydrate | -3162.3[1] | -2676.1[1] | 444[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] |
| SO2 (l) | -320.5[1] | – | – | – |
| SO2 (g) | -296.830[1] | -300.194[1] | 248.22[1] | 39.87[1] |
| SO2 (ao) | -322.980[1] | -300.676[1] | 161.9[1] | – |
* (cr):Crystalline solid, (g):Gas, (l):Liquid, (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°, -1100.8 kJ · mol−1
- ^ ΔfG°, -1012.5 kJ · mol−1
- ^ S°, 145.94 J · K−1 · mol−1
- ^ Cp°, 120.25 J · K−1 · mol−1
- ^ ΔfH°, -1115.87 kJ · mol−1
- ^ ΔfG°, -1010.39 kJ · mol−1
- ^ S°, 87.9 J · K−1 · mol−1
- ^ ΔfH°, -3162.3 kJ · mol−1
- ^ ΔfG°, -2676.1 kJ · mol−1
- ^ S°, 444. J · K−1 · 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°, -320.5 kJ · mol−1
- ^ ΔfH°, -296.830 kJ · mol−1
- ^ ΔfG°, -300.194 kJ · mol−1
- ^ S°, 248.22 J · K−1 · mol−1
- ^ Cp°, 39.87 J · K−1 · mol−1
- ^ ΔfH°, -322.980 kJ · mol−1
- ^ ΔfG°, -300.676 kJ · mol−1
- ^ S°, 161.9 J · K−1 · mol−1