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4H3AsO4 ๐Ÿ”ฅโ†’ 3O2โ†‘ + 2As2O5 + 6H2โ†‘

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Decomposition of arsenic acid
4H3AsO4Arsenic acid
๐Ÿ”ฅ
โŸถ
3O2โ†‘Oxygen + 2As2O5Diarsenic pentaoxide + 6H2โ†‘Hydrogen

Decomposition of arsenic acid yields oxygen, diarsenic pentaoxide, and hydrogen (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 arsenic acid
4H3AsO4Arsenic acid
๐Ÿ”ฅ
โŸถ
3O2โ†‘Oxygen + 2As2O5Diarsenic pentaoxide + 6H2โ†‘Hydrogen

General equation

Thermal decomposition with redox
Thermally decomposable substanceSelf redox agent
๐Ÿ”ฅ
โŸถ
ProductOxidation product + ProductReduction product

Oxidation state of each atom

Decomposition of arsenic acid

Reactants

Chemical formulaNameCoefficientTypeType in general
equation
H3AsO4Arsenic acid4
Self redox agent
Thermally decomposable

Products

Chemical formulaNameCoefficientTypeType in general
equation
O2Oxygen3
Oxidized
โ€“
As2O5Diarsenic pentaoxide2
โ€“
โ€“
H2Hydrogen6
Reduced
โ€“

Thermodynamic changes

Changes in standard condition

Decomposition of arsenic acid
4H3AsO4Crystalline solid
๐Ÿ”ฅ
โŸถ
3O2โ†‘Gas + 2As2O5Crystalline solid + 6H2โ†‘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
1775.5โ€“โ€“โ€“
per 1 mol of
443.88โ€“โ€“โ€“
per 1 mol of
591.83โ€“โ€“โ€“
887.75โ€“โ€“โ€“
per 1 mol of
295.92โ€“โ€“โ€“

Changes in aqueous solution (1)

Decomposition of arsenic acid
4H3AsO4Un-ionized aqueous solution
๐Ÿ”ฅ
โŸถ
3O2โ†‘Gas + 2As2O5Aqueous solution + 6H2โ†‘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
1707.2โ€“โ€“โ€“
per 1 mol of
426.80โ€“โ€“โ€“
per 1 mol of
569.07โ€“โ€“โ€“
853.60โ€“โ€“โ€“
per 1 mol of
284.53โ€“โ€“โ€“

Changes in aqueous solution (2)

Decomposition of arsenic acid
4H3AsO4Un-ionized aqueous solution
๐Ÿ”ฅ
โŸถ
3O2โ†‘Gas + 2As2O5Aqueous solution + 6H2โ†‘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
1682.0โ€“โ€“โ€“
per 1 mol of
420.50โ€“โ€“โ€“
per 1 mol of
560.67โ€“โ€“โ€“
841.00โ€“โ€“โ€“
per 1 mol of
280.33โ€“โ€“โ€“

Changes in aqueous solution (3)

Decomposition of arsenic acid
4H3AsO4Un-ionized aqueous solution
๐Ÿ”ฅ
โŸถ
3O2โ†‘Un-ionized aqueous solution + 2As2O5Aqueous solution + 6H2โ†‘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
1672.1โ€“โ€“โ€“
per 1 mol of
418.02โ€“โ€“โ€“
per 1 mol of
557.37โ€“โ€“โ€“
836.05โ€“โ€“โ€“
per 1 mol of
278.68โ€“โ€“โ€“

Changes in aqueous solution (4)

Decomposition of arsenic acid
4H3AsO4Un-ionized aqueous solution
๐Ÿ”ฅ
โŸถ
3O2โ†‘Un-ionized aqueous solution + 2As2O5Aqueous solution + 6H2โ†‘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
1646.9โ€“โ€“โ€“
per 1 mol of
411.73โ€“โ€“โ€“
per 1 mol of
548.97โ€“โ€“โ€“
823.45โ€“โ€“โ€“
per 1 mol of
274.48โ€“โ€“โ€“

Changes in aqueous solution (5)

Decomposition of arsenic acid
4H3AsO4Aqueous solution
๐Ÿ”ฅ
โŸถ
3O2โ†‘Gas + 2As2O5Aqueous solution + 6H2โ†‘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
1715.6โ€“โ€“โ€“
per 1 mol of
428.90โ€“โ€“โ€“
per 1 mol of
571.87โ€“โ€“โ€“
857.80โ€“โ€“โ€“
per 1 mol of
285.93โ€“โ€“โ€“

Changes in aqueous solution (6)

Decomposition of arsenic acid
4H3AsO4Aqueous solution
๐Ÿ”ฅ
โŸถ
3O2โ†‘Gas + 2As2O5Aqueous solution + 6H2โ†‘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
1690.4โ€“โ€“โ€“
per 1 mol of
422.60โ€“โ€“โ€“
per 1 mol of
563.47โ€“โ€“โ€“
845.20โ€“โ€“โ€“
per 1 mol of
281.73โ€“โ€“โ€“

Changes in aqueous solution (7)

Decomposition of arsenic acid
4H3AsO4Aqueous solution
๐Ÿ”ฅ
โŸถ
3O2โ†‘Un-ionized aqueous solution + 2As2O5Aqueous solution + 6H2โ†‘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
1680.5โ€“โ€“โ€“
per 1 mol of
420.13โ€“โ€“โ€“
per 1 mol of
560.17โ€“โ€“โ€“
840.25โ€“โ€“โ€“
per 1 mol of
280.08โ€“โ€“โ€“

Changes in aqueous solution (8)

Decomposition of arsenic acid
4H3AsO4Aqueous solution
๐Ÿ”ฅ
โŸถ
3O2โ†‘Un-ionized aqueous solution + 2As2O5Aqueous solution + 6H2โ†‘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
1655.3โ€“โ€“โ€“
per 1 mol of
413.82โ€“โ€“โ€“
per 1 mol of
551.77โ€“โ€“โ€“
827.65โ€“โ€“โ€“
per 1 mol of
275.88โ€“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
H3AsO4 (cr)-906.3[1]โ€“โ€“โ€“
H3AsO4 (ao)-902.5[1]-766.0[1]184[1]โ€“
H3AsO4 (aq)-904.6[1]โ€“โ€“โ€“
* (cr):Crystalline solid, (ao):Un-ionized aqueous solution, (aq):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
O2 (g)0[1]0[1]205.138[1]29.355[1]
O2 (ao)-11.7[1]16.4[1]110.9[1]โ€“
As2O5 (cr)-924.87[1]-782.3[1]105.4[1]116.52[1]
As2O5 (aq)-951.4[1]โ€“โ€“โ€“
As2O5 (cr)
4 hydrate
-2104.6[1]โ€“โ€“โ€“
H2 (g)0[1]0[1]130.684[1]28.824[1]
H2 (ao)-4.2[1]17.6[1]577[1]โ€“
* (g):Gas, (ao):Un-ionized aqueous solution, (cr):Crystalline solid, (aq):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)