NH4CN 🔥→ HCN + NH3↑
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- Decomposition of ammonium cyanide
Decomposition of ammonium cyanide yields hydrogen cyanide and ammonia (Other reactions are here). This reaction is an acid-base reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Decomposition of ammonium cyanide
General equation
- Thermal decomposition without redox
- Thermally decomposable substanceLewis conjugate🔥⟶ ProductLewis acid + ProductLewis base
- Thermal decomposition of salt of hydracid and non hydroxide base
- Salt of hydracid and non hydroxide base🔥⟶ Non hydroxide baseConjugate base + HydracidConjugate acid
Oxidation state of each atom
- Decomposition of ammonium cyanide
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| NH4CN | Ammonium cyanide | 1 | Lewis conjugate – | Thermally decomposable Salt of hydracid and non hydroxide base |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| HCN | Hydrogen cyanide | 1 | Lewis acid Conjugate acid | – Hydracid |
| NH3 | Ammonia | 1 | Lewis acid Conjugate base | – Non hydroxide base |
Thermodynamic changes
Changes in standard condition
- Decomposition of ammonium cyanide
| 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 | 62.34 | – | – | −28 |
per 1 mol of | 62.34 | – | – | −28 |
per 1 mol of | 62.34 | – | – | −28 |
per 1 mol of | 62.34 | – | – | −28 |
Changes in aqueous solution (1)
- Decomposition of ammonium cyanide◆
ΔrG 10.3 kJ/mol K 0.16 × 10−1 pK 1.80
| 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 | 43.0 | 10.3 | 109.7 | – |
per 1 mol of | 43.0 | 10.3 | 109.7 | – |
per 1 mol of | 43.0 | 10.3 | 109.7 | – |
per 1 mol of | 43.0 | 10.3 | 109.7 | – |
Changes in aqueous solution (2)
- Decomposition of ammonium cyanide◆
ΔrG 0.2 kJ/mol K 0.92 × 100 pK 0.04
| 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 | 8.8 | 0.2 | 28.5 | – |
per 1 mol of | 8.8 | 0.20 | 28.5 | – |
per 1 mol of | 8.8 | 0.20 | 28.5 | – |
per 1 mol of | 8.8 | 0.20 | 28.5 | – |
Changes in aqueous solution (3)
- Decomposition of ammonium cyanide
| 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 | 28.8 | – | – | – |
per 1 mol of | 28.8 | – | – | – |
per 1 mol of | 28.8 | – | – | – |
per 1 mol of | 28.8 | – | – | – |
Changes in aqueous solution (4)
- Decomposition of ammonium cyanide
| 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 | −5.4 | – | – | – |
per 1 mol of | −5.4 | – | – | – |
per 1 mol of | −5.4 | – | – | – |
per 1 mol of | −5.4 | – | – | – |
Changes in aqueous solution (5)
- Decomposition of ammonium cyanide◆
ΔrG 63.0 kJ/mol K 0.92 × 10−11 pK 11.04
| 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 | 86.5 | 63.0 | 79.1 | – |
per 1 mol of | 86.5 | 63.0 | 79.1 | – |
per 1 mol of | 86.5 | 63.0 | 79.1 | – |
per 1 mol of | 86.5 | 63.0 | 79.1 | – |
Changes in aqueous solution (6)
- Decomposition of ammonium cyanide◆
ΔrG 52.9 kJ/mol K 0.54 × 10−9 pK 9.27
| 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 | 52.3 | 52.9 | −2.1 | – |
per 1 mol of | 52.3 | 52.9 | −2.1 | – |
per 1 mol of | 52.3 | 52.9 | −2.1 | – |
per 1 mol of | 52.3 | 52.9 | −2.1 | – |
Changes in aqueous solution (7)
- Decomposition of ammonium cyanide
| 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 | 72.3 | – | – | – |
per 1 mol of | 72.3 | – | – | – |
per 1 mol of | 72.3 | – | – | – |
per 1 mol of | 72.3 | – | – | – |
Changes in aqueous solution (8)
- Decomposition of ammonium cyanide
| 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 | 38.1 | – | – | – |
per 1 mol of | 38.1 | – | – | – |
per 1 mol of | 38.1 | – | – | – |
per 1 mol of | 38.1 | – | – | – |
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 |
|---|---|---|---|---|
| NH4CN (cr) | 0.42[1] | – | – | 134[1] |
| NH4CN (ai) | 18.0[1] | 93.0[1] | 207.5[1] | – |
| NH4CN (aq) | 32.2[1] | – | – | – |
* (cr):Crystalline solid, (ai):Ionized aqueous solution, (aq):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 |
|---|---|---|---|---|
| HCN (l) | 108.87[1] | 124.97[1] | 112.84[1] | 70.63[1] |
| HCN (g) | 135.1[1] | 124.7[1] | 201.78[1] | 35.86[1] |
| HCN (ai) | 150.6[1] | 172.4[1] | 94.1[1] | – |
| HCN (ao) | 107.1[1] | 119.7[1] | 124.7[1] | – |
| NH3 (g) | -46.11[1] | -16.45[1] | 192.45[1] | 35.06[1] |
| NH3 (ao) | -80.29[1] | -26.50[1] | 111.3[1] | – |
* (l):Liquid, (g):Gas, (ai):Ionized aqueous solution, (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°, 0.42 kJ · mol−1
- ^ Cp°, 134. J · K−1 · mol−1
- ^ ΔfH°, 18.0 kJ · mol−1
- ^ ΔfG°, 93.0 kJ · mol−1
- ^ S°, 207.5 J · K−1 · mol−1
- ^ ΔfH°, 32.2 kJ · mol−1
- ^ ΔfH°, 108.87 kJ · mol−1
- ^ ΔfG°, 124.97 kJ · mol−1
- ^ S°, 112.84 J · K−1 · mol−1
- ^ Cp°, 70.63 J · K−1 · mol−1
- ^ ΔfH°, 135.1 kJ · mol−1
- ^ ΔfG°, 124.7 kJ · mol−1
- ^ S°, 201.78 J · K−1 · mol−1
- ^ Cp°, 35.86 J · K−1 · mol−1
- ^ ΔfH°, 150.6 kJ · mol−1
- ^ ΔfG°, 172.4 kJ · mol−1
- ^ S°, 94.1 J · K−1 · mol−1
- ^ ΔfH°, 107.1 kJ · mol−1
- ^ ΔfG°, 119.7 kJ · mol−1
- ^ S°, 124.7 J · K−1 · mol−1
- ^ ΔfH°, -46.11 kJ · mol−1
- ^ ΔfG°, -16.45 kJ · mol−1
- ^ S°, 192.45 J · K−1 · mol−1
- ^ Cp°, 35.06 J · K−1 · mol−1
- ^ ΔfH°, -80.29 kJ · mol−1
- ^ ΔfG°, -26.50 kJ · mol−1
- ^ S°, 111.3 J · K−1 · mol−1