NH4SCN 🔥→ S + N2H4 + C
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- Decomposition of ammonium thiocyanate
Decomposition of ammonium thiocyanate yields , hydrazine, 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 ammonium thiocyanate
General equation
- Thermal decomposition with redox
- Thermally decomposable substanceSelf redox agent🔥⟶ ProductOxidation product + ProductReduction product
Oxidation state of each atom
- Decomposition of ammonium thiocyanate
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| NH4SCN | Ammonium thiocyanate | 1 | Self redox agent | Thermally decomposable |
Products
Thermodynamic changes
Changes in standard condition (1)
- Decomposition of ammonium thiocyanate
| 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 | 129.3 | – | – | – |
per 1 mol of | 129.3 | – | – | – |
| 129.3 | – | – | – | |
per 1 mol of | 129.3 | – | – | – |
| 129.3 | – | – | – |
Changes in standard condition (2)
- Decomposition of ammonium thiocyanate
| 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 | 131.2 | – | – | – |
per 1 mol of | 131.2 | – | – | – |
| 131.2 | – | – | – | |
per 1 mol of | 131.2 | – | – | – |
| 131.2 | – | – | – |
Changes in standard condition (3)
- Decomposition of ammonium thiocyanate
| 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 | 129.7 | – | – | – |
per 1 mol of | 129.7 | – | – | – |
| 129.7 | – | – | – | |
per 1 mol of | 129.7 | – | – | – |
| 129.7 | – | – | – |
Changes in standard condition (4)
- Decomposition of ammonium thiocyanate
| 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 | 131.6 | – | – | – |
per 1 mol of | 131.6 | – | – | – |
| 131.6 | – | – | – | |
per 1 mol of | 131.6 | – | – | – |
| 131.6 | – | – | – |
Changes in aqueous solution
- Decomposition of ammonium thiocyanate◆
ΔrG 114.7 kJ/mol K 0.80 × 10−20 pK 20.09
| 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 | 90.38 | 114.7 | −82 | – |
per 1 mol of | 90.38 | 114.7 | −82 | – |
| 90.38 | 114.7 | −82 | – | |
per 1 mol of | 90.38 | 114.7 | −82 | – |
| 90.38 | 114.7 | −82 | – |
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 |
|---|---|---|---|---|
| NH4SCN (cr) | -78.7[1] | – | – | – |
| NH4SCN (ai) | -56.07[1] | 13.40[1] | 257.7[1] | 39.7[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 |
|---|---|---|---|---|
| (cr) rhombic | 0[1] | 0[1] | 31.80[1] | 22.64[1] |
| (cr) monoclinic | 0.33[1] | – | – | – |
| (g) | 278.805[1] | 238.250[1] | 167.821[1] | 23.673[1] |
| N2H4 (l) | 50.63[1] | 149.34[1] | 121.21[1] | 98.87[1] |
| N2H4 (g) | 95.40[1] | 159.35[1] | 238.47[1] | 49.58[1] |
| N2H4 (ao) | 34.31[1] | 128.1[1] | 138[1] | – |
| (cr) graphite | 0[1] | 0[1] | 5.740[1] | 8.527[1] |
| (cr) diamond | 1.895[1] | 2.900[1] | 2.377[1] | 6.113[1] |
| (g) | 716.682[1] | 671.257[1] | 158.096[1] | 20.838[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°, -78.7 kJ · mol−1
- ^ ΔfH°, -56.07 kJ · mol−1
- ^ ΔfG°, 13.40 kJ · mol−1
- ^ S°, 257.7 J · K−1 · mol−1
- ^ Cp°, 39.7 J · K−1 · mol−1
- ^ ΔfH°, 0 kJ · mol−1
- ^ ΔfG°, 0 kJ · mol−1
- ^ S°, 31.80 J · K−1 · mol−1
- ^ Cp°, 22.64 J · K−1 · mol−1
- ^ ΔfH°, 0.33 kJ · mol−1
- ^ ΔfH°, 278.805 kJ · mol−1
- ^ ΔfG°, 238.250 kJ · mol−1
- ^ S°, 167.821 J · K−1 · mol−1
- ^ Cp°, 23.673 J · K−1 · mol−1
- ^ ΔfH°, 50.63 kJ · mol−1
- ^ ΔfG°, 149.34 kJ · mol−1
- ^ S°, 121.21 J · K−1 · mol−1
- ^ Cp°, 98.87 J · K−1 · mol−1
- ^ ΔfH°, 95.40 kJ · mol−1
- ^ ΔfG°, 159.35 kJ · mol−1
- ^ S°, 238.47 J · K−1 · mol−1
- ^ Cp°, 49.58 J · K−1 · mol−1
- ^ ΔfH°, 34.31 kJ · mol−1
- ^ ΔfG°, 128.1 kJ · mol−1
- ^ S°, 138. J · K−1 · mol−1
- ^ ΔfH°, 0 kJ · mol−1
- ^ ΔfG°, 0 kJ · mol−1
- ^ S°, 5.740 J · K−1 · mol−1
- ^ Cp°, 8.527 J · K−1 · mol−1
- ^ ΔfH°, 1.895 kJ · mol−1
- ^ ΔfG°, 2.900 kJ · mol−1
- ^ S°, 2.377 J · K−1 · mol−1
- ^ Cp°, 6.113 J · K−1 · mol−1
- ^ ΔfH°, 716.682 kJ · mol−1
- ^ ΔfG°, 671.257 kJ · mol−1
- ^ S°, 158.096 J · K−1 · mol−1
- ^ Cp°, 20.838 J · K−1 · mol−1