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  3. 15(NH4)2Cr2O7 ๐Ÿ”ฅโ†’ 18NOโ†‘ + 28Cr(OH)3 + Cr2O3 + 12NH3โ†‘

15(NH4)2Cr2O7 ๐Ÿ”ฅโ†’ 18NOโ†‘ + 28Cr(OH)3 + Cr2O3 + 12NH3โ†‘

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Decomposition of ammonium dichromate
15(NH4)2Cr2O7Ammonium dichromate
๐Ÿ”ฅ
โŸถ
18NOโ†‘Nitrogen monoxide + 28Cr(OH)3Chromium(III) hydroxide + Cr2O3Chromium(III) oxide + 12NH3โ†‘Ammonia

Decomposition of ammonium dichromate yields nitrogen monoxide, chromium(III) hydroxide, chromium(III) oxide, and ammonia (Other reactions are here). This reaction is an oxidation-reduction reaction and is classified as follows:

Table of contents
  1. 1Reaction data
  2. 2Thermodynamic changes
  3. 3References
  4. 4Related reactions
  5. 5Related categories

Reaction data

Chemical equation

Decomposition of ammonium dichromate
15(NH4)2Cr2O7Ammonium dichromate
๐Ÿ”ฅ
โŸถ
18NOโ†‘Nitrogen monoxide + 28Cr(OH)3Chromium(III) hydroxide + Cr2O3Chromium(III) oxide + 12NH3โ†‘Ammonia

General equation

Thermal decomposition with redox
Thermally decomposable substanceSelf redox agent
๐Ÿ”ฅ
โŸถ
ProductOxidation product + ProductReduction product
Thermal decomposition of oxoacid salt with redox
Oxoacid saltSelf redox agent
๐Ÿ”ฅ
โŸถ
ProductOxidation product + ProductReduction product

Oxidation state of each atom

Decomposition of ammonium dichromate

Reactants

Chemical formulaNameCoefficientTypeType in general
equation
(NH4)2Cr2O7Ammonium dichromate15
Self redox agent
Thermally decomposable
Oxoacid salt

Products

Chemical formulaNameCoefficientTypeType in general
equation
NONitrogen monoxide18
Oxidized
โ€“
Cr(OH)3Chromium(III) hydroxide28
Reduced
โ€“
Cr2O3Chromium(III) oxide1
Reduced
โ€“
NH3Ammonia12
โ€“
โ€“

Thermodynamic changes

Changes in standard condition

Decomposition of ammonium dichromate
15(NH4)2Cr2O7Crystalline solid
๐Ÿ”ฅ
โŸถ
18NOโ†‘Gas + 28Cr(OH)3Crystalline solidprecipitated + Cr2O3Crystalline solid + 12NH3โ†‘Gas
Standard enthalpy
of reaction
ฮ”rHยฐ
kJ ยท molโˆ’1		Standard
Gibbs energy
of reaction
ฮ”rGยฐ
kJ ยท molโˆ’1		Standard entropy
of reaction
ฮ”rSยฐ
J ยท Kโˆ’1 ยท molโˆ’1		Standard heat
capacity of reaction
at constant pressure
ฮ”rCpยฐ
J ยท Kโˆ’1 ยท molโˆ’1
per 1 mol of
Equation
โˆ’2760.0โ€“โ€“โ€“
โˆ’184.00โ€“โ€“โ€“
per 1 mol of
โˆ’153.33โ€“โ€“โ€“
โˆ’98.571โ€“โ€“โ€“
โˆ’2760.0โ€“โ€“โ€“
per 1 mol of
โˆ’230.00โ€“โ€“โ€“

Changes in aqueous solution (1)

Decomposition of ammonium dichromate
15(NH4)2Cr2O7Ionized aqueous solution
๐Ÿ”ฅ
โŸถ
18NOโ†‘Gas + 28Cr(OH)3Crystalline solidprecipitated + Cr2O3Crystalline solid + 12NH3โ†‘Gas
Standard enthalpy
of reaction
ฮ”rHยฐ
kJ ยท molโˆ’1		Standard
Gibbs energy
of reaction
ฮ”rGยฐ
kJ ยท molโˆ’1		Standard entropy
of reaction
ฮ”rSยฐ
J ยท Kโˆ’1 ยท molโˆ’1		Standard heat
capacity of reaction
at constant pressure
ฮ”rCpยฐ
J ยท Kโˆ’1 ยท molโˆ’1
per 1 mol of
Equation
โˆ’3532.5โ€“โ€“โ€“
โˆ’235.50โ€“โ€“โ€“
per 1 mol of
โˆ’196.25โ€“โ€“โ€“
โˆ’126.16โ€“โ€“โ€“
โˆ’3532.5โ€“โ€“โ€“
per 1 mol of
โˆ’294.38โ€“โ€“โ€“

Changes in aqueous solution (2)

Decomposition of ammonium dichromate
15(NH4)2Cr2O7Ionized aqueous solution
๐Ÿ”ฅ
โŸถ
18NOโ†‘Gas + 28Cr(OH)3Crystalline solidprecipitated + Cr2O3Crystalline solid + 12NH3โ†‘Un-ionized aqueous solution
Standard enthalpy
of reaction
ฮ”rHยฐ
kJ ยท molโˆ’1		Standard
Gibbs energy
of reaction
ฮ”rGยฐ
kJ ยท molโˆ’1		Standard entropy
of reaction
ฮ”rSยฐ
J ยท Kโˆ’1 ยท molโˆ’1		Standard heat
capacity of reaction
at constant pressure
ฮ”rCpยฐ
J ยท Kโˆ’1 ยท molโˆ’1
per 1 mol of
Equation
โˆ’3942.7โ€“โ€“โ€“
โˆ’262.85โ€“โ€“โ€“
per 1 mol of
โˆ’219.04โ€“โ€“โ€“
โˆ’140.81โ€“โ€“โ€“
โˆ’3942.7โ€“โ€“โ€“
per 1 mol of
โˆ’328.56โ€“โ€“โ€“

Thermodynamic data of reactants

Chemical formulaStandard enthalpy
of formation
ฮ”fHยฐ
kJ ยท molโˆ’1		Standard Gibbs
energy of
formation
ฮ”fGยฐ
kJ ยท molโˆ’1		Standard
molar entropy
Sยฐ
J ยท Kโˆ’1 ยท molโˆ’1		Standard molar
heat capacity at
constant pressure
Cpยฐ
J ยท Kโˆ’1 ยท molโˆ’1
(NH4)2Cr2O7 (cr)-1806.7[1]โ€“โ€“โ€“
(NH4)2Cr2O7 (ai)-1755.2[1]-1459.5[1]488.7[1]โ€“
* (cr):Crystalline solid, (ai):Ionized aqueous solution

Thermodynamic data of products

Chemical formulaStandard enthalpy
of formation
ฮ”fHยฐ
kJ ยท molโˆ’1		Standard Gibbs
energy of
formation
ฮ”fGยฐ
kJ ยท molโˆ’1		Standard
molar entropy
Sยฐ
J ยท Kโˆ’1 ยท molโˆ’1		Standard molar
heat capacity at
constant pressure
Cpยฐ
J ยท Kโˆ’1 ยท molโˆ’1
NO (g)90.25[1]86.55[1]210.761[1]29.844[1]
Cr(OH)3 (cr)
precipitated
-1064.0[1]โ€“โ€“โ€“
Cr2O3 (cr)-1139.7[1]-1058.1[1]81.2[1]118.74[1]
Cr2O3 (cr)
1 hydrate
-1506[1]โ€“โ€“โ€“
Cr2O3 (cr)
2 hydrate
-1845[1]โ€“โ€“โ€“
Cr2O3 (cr)
3 hydrate
-2171[1]โ€“โ€“โ€“
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]โ€“
* (g):Gas, (cr):Crystalline solid, (ao):Un-ionized aqueous solution

References

List of references

  1. 1
    Janiel J. Reed (1989)
    The NBS Tables of Chemical Thermodynamic Properties: Selected Values for Inorganic and C1 and C2 Organic Substances in SI Units
    National Institute of Standards and Technology (NIST)