2NH4+ + 2HCrO4− → (NH4)2Cr2O7 + H2O
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- Reaction of ammonium ion and hydrogenchromate ion
The reaction of ammonium ion and hydrogenchromate ion yields ammonium dichromate and water. This reaction is an acid-base reaction and is classified as follows:
Table of contents
Reaction data
Chemical equation
- Reaction of ammonium ion and hydrogenchromate ion
General equation
- Reaction of cation and anion
- CationLewis acid + AnionLewis base ⟶ ProductLewis conjugate + (H2O)
Oxidation state of each atom
- Reaction of ammonium ion and hydrogenchromate ion
Reactants
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| NH4+ | Ammonium ion | 2 | Lewis acid | Cation |
| HCrO4− | Hydrogenchromate ion | 2 | Lewis base | Anion |
Products
| Chemical formula | Name | Coefficient | Type | Type in general equation |
|---|---|---|---|---|
| (NH4)2Cr2O7 | Ammonium dichromate | 1 | Lewis conjugate | – |
| H2O | Water | 1 | – | Water |
Thermodynamic changes
Changes in standard condition
- Reaction of ammonium ion and hydrogenchromate ion◆
ΔrG −8.6 kJ/mol K 3.21 × 101 pK −1.51 - 2NH4+Un-ionized aqueous solution + 2HCrO4−Un-ionized aqueous solution(NH4)2Cr2O7Ionized aqueous solution + H2OLiquid⟶
| 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 | −19.6 | −8.6 | −36.4 | – |
per 1 mol of Ammonium ion | −9.80 | −4.3 | −18.2 | – |
per 1 mol of Hydrogenchromate ion | −9.80 | −4.3 | −18.2 | – |
per 1 mol of | −19.6 | −8.6 | −36.4 | – |
per 1 mol of | −19.6 | −8.6 | −36.4 | – |
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 |
|---|---|---|---|---|
| NH4+ (ao) | -132.51[1] | -79.31[1] | 113.4[1] | 79.9[1] |
| HCrO4− (ao) | -878.2[1] | -764.7[1] | 184.1[1] | – |
* (ao):Un-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 |
|---|---|---|---|---|
| (NH4)2Cr2O7 (cr) | -1806.7[1] | – | – | – |
| (NH4)2Cr2O7 (ai) | -1755.2[1] | -1459.5[1] | 488.7[1] | – |
| H2O (cr) | – | – | – | – |
| H2O (l) | -285.830[1] | -237.129[1] | 69.91[1] | 75.291[1] |
| H2O (g) | -241.818[1] | -228.572[1] | 188.825[1] | 33.577[1] |
* (cr):Crystalline solid, (ai):Ionized aqueous solution, (l):Liquid, (g):Gas
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°, -132.51 kJ · mol−1
- ^ ΔfG°, -79.31 kJ · mol−1
- ^ S°, 113.4 J · K−1 · mol−1
- ^ Cp°, 79.9 J · K−1 · mol−1
- ^ ΔfH°, -878.2 kJ · mol−1
- ^ ΔfG°, -764.7 kJ · mol−1
- ^ S°, 184.1 J · K−1 · mol−1
- ^ ΔfH°, -1806.7 kJ · mol−1
- ^ ΔfH°, -1755.2 kJ · mol−1
- ^ ΔfG°, -1459.5 kJ · mol−1
- ^ S°, 488.7 J · K−1 · mol−1
- ^ ΔfH°, -285.830 kJ · mol−1
- ^ ΔfG°, -237.129 kJ · mol−1
- ^ S°, 69.91 J · K−1 · mol−1
- ^ Cp°, 75.291 J · K−1 · mol−1
- ^ ΔfH°, -241.818 kJ · mol−1
- ^ ΔfG°, -228.572 kJ · mol−1
- ^ S°, 188.825 J · K−1 · mol−1
- ^ Cp°, 33.577 J · K−1 · mol−1