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2H2SeO3 ๐Ÿ”ฅโ†’ O2โ†‘ + 2SeO2 + 2H2โ†‘

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Decomposition of selenous acid
2H2SeO3Selenous acid
๐Ÿ”ฅ
โŸถ
O2โ†‘Oxygen + 2SeO2Selenium dioxide + 2H2โ†‘Hydrogen

Decomposition of selenous acid yields oxygen, selenium dioxide, 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 selenous acid
2H2SeO3Selenous acid
๐Ÿ”ฅ
โŸถ
O2โ†‘Oxygen + 2SeO2Selenium dioxide + 2H2โ†‘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 selenous acid

Reactants

Chemical formulaNameCoefficientTypeType in general
equation
H2SeO3Selenous acid2
Self redox agent
Thermally decomposable

Products

Chemical formulaNameCoefficientTypeType in general
equation
O2Oxygen1
Oxidized
โ€“
SeO2Selenium dioxide2
โ€“
โ€“
H2Hydrogen2
Reduced
โ€“

Thermodynamic changes

Changes in standard condition

Decomposition of selenous acid
2H2SeO3Crystalline solid
๐Ÿ”ฅ
โŸถ
O2โ†‘Gas + 2SeO2Crystalline solid + 2H2โ†‘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
598.22โ€“โ€“โ€“
per 1 mol of
299.11โ€“โ€“โ€“
per 1 mol of
598.22โ€“โ€“โ€“
per 1 mol of
299.11โ€“โ€“โ€“
per 1 mol of
299.11โ€“โ€“โ€“

Changes in aqueous solution (1)

Decomposition of selenous acid
2H2SeO3Un-ionized aqueous solution
๐Ÿ”ฅ
โŸถ
O2โ†‘Gas + 2SeO2Aqueous solution + 2H2โ†‘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
571.70โ€“โ€“โ€“
per 1 mol of
285.85โ€“โ€“โ€“
per 1 mol of
571.70โ€“โ€“โ€“
per 1 mol of
285.85โ€“โ€“โ€“
per 1 mol of
285.85โ€“โ€“โ€“

Changes in aqueous solution (2)

Decomposition of selenous acid
2H2SeO3Un-ionized aqueous solution
๐Ÿ”ฅ
โŸถ
O2โ†‘Gas + 2SeO2Aqueous solution + 2H2โ†‘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
563.3โ€“โ€“โ€“
per 1 mol of
281.6โ€“โ€“โ€“
per 1 mol of
563.3โ€“โ€“โ€“
per 1 mol of
281.6โ€“โ€“โ€“
per 1 mol of
281.6โ€“โ€“โ€“

Changes in aqueous solution (3)

Decomposition of selenous acid
2H2SeO3Un-ionized aqueous solution
๐Ÿ”ฅ
โŸถ
O2โ†‘Un-ionized aqueous solution + 2SeO2Aqueous solution + 2H2โ†‘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
560.0โ€“โ€“โ€“
per 1 mol of
280.0โ€“โ€“โ€“
per 1 mol of
560.0โ€“โ€“โ€“
per 1 mol of
280.0โ€“โ€“โ€“
per 1 mol of
280.0โ€“โ€“โ€“

Changes in aqueous solution (4)

Decomposition of selenous acid
2H2SeO3Un-ionized aqueous solution
๐Ÿ”ฅ
โŸถ
O2โ†‘Un-ionized aqueous solution + 2SeO2Aqueous solution + 2H2โ†‘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
551.6โ€“โ€“โ€“
per 1 mol of
275.8โ€“โ€“โ€“
per 1 mol of
551.6โ€“โ€“โ€“
per 1 mol of
275.8โ€“โ€“โ€“
per 1 mol of
275.8โ€“โ€“โ€“

Changes in aqueous solution (5)

Decomposition of selenous acid
2H2SeO3Aqueous solution
๐Ÿ”ฅ
โŸถ
O2โ†‘Gas + 2SeO2Aqueous solution + 2H2โ†‘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
571.28โ€“โ€“โ€“
per 1 mol of
285.64โ€“โ€“โ€“
per 1 mol of
571.28โ€“โ€“โ€“
per 1 mol of
285.64โ€“โ€“โ€“
per 1 mol of
285.64โ€“โ€“โ€“

Changes in aqueous solution (6)

Decomposition of selenous acid
2H2SeO3Aqueous solution
๐Ÿ”ฅ
โŸถ
O2โ†‘Gas + 2SeO2Aqueous solution + 2H2โ†‘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
562.9โ€“โ€“โ€“
per 1 mol of
281.4โ€“โ€“โ€“
per 1 mol of
562.9โ€“โ€“โ€“
per 1 mol of
281.4โ€“โ€“โ€“
per 1 mol of
281.4โ€“โ€“โ€“

Changes in aqueous solution (7)

Decomposition of selenous acid
2H2SeO3Aqueous solution
๐Ÿ”ฅ
โŸถ
O2โ†‘Un-ionized aqueous solution + 2SeO2Aqueous solution + 2H2โ†‘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
559.6โ€“โ€“โ€“
per 1 mol of
279.8โ€“โ€“โ€“
per 1 mol of
559.6โ€“โ€“โ€“
per 1 mol of
279.8โ€“โ€“โ€“
per 1 mol of
279.8โ€“โ€“โ€“

Changes in aqueous solution (8)

Decomposition of selenous acid
2H2SeO3Aqueous solution
๐Ÿ”ฅ
โŸถ
O2โ†‘Un-ionized aqueous solution + 2SeO2Aqueous solution + 2H2โ†‘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
551.2โ€“โ€“โ€“
per 1 mol of
275.6โ€“โ€“โ€“
per 1 mol of
551.2โ€“โ€“โ€“
per 1 mol of
275.6โ€“โ€“โ€“
per 1 mol of
275.6โ€“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
H2SeO3 (cr)-524.46[1]โ€“โ€“โ€“
H2SeO3 (ao)-507.48[1]-426.14[1]207.9[1]โ€“
H2SeO3 (aq)-507.27[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€“
SeO2 (cr)-225.35[1]โ€“โ€“โ€“
SeO2 (aq)-221.63[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)