4KNO3 🔥→ 2K2O + 4NO2↑ + O2↑
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- Decomposition of potassium nitrate
Decomposition of potassium nitrate yields potassium oxide, nitrogen dioxide, 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 nitrate
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 nitrate
Reactants
Chemical formula | Name | Coefficient | Type | Type in general equation |
---|---|---|---|---|
KNO3 | Potassium nitrate | 4 | Self redox agent | Thermally decomposable Oxoacid salt |
Products
Chemical formula | Name | Coefficient | Type | Type in general equation |
---|---|---|---|---|
K2O | Potassium oxide | 2 | – | – |
NO2 | Nitrogen dioxide | 4 | Reduced | – |
1 | Oxidized | – |
Thermodynamic changes
Changes in standard condition
- Decomposition of potassium nitrate◆
ΔrG 1140.5 kJ/mol K 0.16 × 10−199 pK 199.81
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 | 1388.2 | 1140.5 | 821.4 | −40.0 |
per 1 mol of | 347.05 | 285.13 | 205.3 | −10.0 |
per 1 mol of | 694.10 | 570.25 | 410.7 | −20.0 |
per 1 mol of | 347.05 | 285.13 | 205.3 | −10.0 |
1388.2 | 1140.5 | 821.4 | −40.0 |
Changes in aqueous solution (1)
- Decomposition of potassium nitrate◆
ΔrG 1139.2 kJ/mol K 0.26 × 10−199 pK 199.58
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 | 1248.7 | 1139.2 | 358.0 | 605.2 |
per 1 mol of | 312.18 | 284.80 | 89.50 | 151.3 |
per 1 mol of | 624.35 | 569.60 | 179.0 | 302.6 |
per 1 mol of | 312.18 | 284.80 | 89.50 | 151.3 |
1248.7 | 1139.2 | 358.0 | 605.2 |
Changes in aqueous solution (2)
- Decomposition of potassium nitrate◆
ΔrG 1155.6 kJ/mol K 0.35 × 10−202 pK 202.45
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 | 1237.0 | 1155.6 | 263.7 | – |
per 1 mol of | 309.25 | 288.90 | 65.92 | – |
per 1 mol of | 618.50 | 577.80 | 131.8 | – |
per 1 mol of | 309.25 | 288.90 | 65.92 | – |
1237.0 | 1155.6 | 263.7 | – |
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 |
---|---|---|---|---|
KNO3 (cr) | -494.63[1] | -394.86[1] | 133.05[1] | 96.40[1] |
KNO3 (ai) | -459.74[1] | -394.53[1] | 248.9[1] | -64.9[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 |
---|---|---|---|---|
K2O (cr) | -361.5[1] | -322.1[2] | 94.1[2] | 83.7[2] |
K2O (g) | -63[1] | – | – | – |
NO2 (g) | 33.18[1] | 51.31[1] | 240.06[1] | 37.20[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, (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°, -494.63 kJ · mol−1
- ^ ΔfG°, -394.86 kJ · mol−1
- ^ S°, 133.05 J · K−1 · mol−1
- ^ Cp°, 96.40 J · K−1 · mol−1
- ^ ΔfH°, -459.74 kJ · mol−1
- ^ ΔfG°, -394.53 kJ · mol−1
- ^ S°, 248.9 J · K−1 · mol−1
- ^ Cp°, -64.9 J · K−1 · mol−1
- ^ ΔfH°, -361.5 kJ · mol−1
- ^ ΔfH°, -63. kJ · mol−1
- ^ ΔfH°, 33.18 kJ · mol−1
- ^ ΔfG°, 51.31 kJ · mol−1
- ^ S°, 240.06 J · K−1 · mol−1
- ^ Cp°, 37.20 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