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Ca(OH)2 + SO3 → CaSO4 + H2O

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Reaction of calcium hydroxide and sulfur trioxide
Ca(OH)2Calcium hydroxide + SO3Sulfur trioxide
⟶
CaSO4Calcium sulfate + H2OWater

The reaction of calcium hydroxide and sulfur trioxide yields calcium sulfate and water (Other reactions are here). This reaction is an acid-base 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

Reaction of calcium hydroxide and sulfur trioxide
Ca(OH)2Calcium hydroxide + SO3Sulfur trioxide
⟶
CaSO4Calcium sulfate + H2OWater

General equation

Reaction of base and acidic oxide
BaseLewis base + Acidic oxideLewis acid + H2O
⟶
Oxoacid saltLewis conjugate + (H2O)
Reaction of hydroxide base and acidic oxide
Hydroxide baseLewis base + Acidic oxideLewis acid
⟶
Oxoacid saltLewis conjugate + H2O
Reaction of strong hydroxide base and strongly acidic oxide
Strong hydroxide baseLewis base + Strongly acidic oxideLewis acid
⟶
Salt of strong acid and strong baseLewis conjugate + H2O

Oxidation state of each atom

Reaction of calcium hydroxide and sulfur trioxide

Reactants

Chemical formulaNameCoefficientTypeType in general
equation
Ca(OH)2Calcium hydroxide1
Lewis base
Base
Hydroxide base
Strong hydroxide base
SO3Sulfur trioxide1
Lewis acid
Acidic oxide
Strongly acidic oxide

Products

Chemical formulaNameCoefficientTypeType in general
equation
CaSO4Calcium sulfate1
Lewis conjugate
Oxoacid salt
Salt of strong acid and strong base
H2OWater1
–
Water

Thermodynamic changes

Changes in standard condition (1)

Reaction of calcium hydroxide and sulfur trioxide
◆
ΔrG−286.68 kJ/mol
K1.68 × 1050
pK−50.22
Ca(OH)2Crystalline solid + SO3Liquid
⟶
CaSO4Crystalline solidinsoluble, anhydrite + 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
−292.81−286.68−20.6–
per 1 mol of
−292.81−286.68−20.6–
per 1 mol of
−292.81−286.68−20.6–
per 1 mol of
−292.81−286.68−20.6–
per 1 mol of
−292.81−286.68−20.6–

Changes in standard condition (2)

Reaction of calcium hydroxide and sulfur trioxide
◆
ΔrG−278.31 kJ/mol
K5.73 × 1048
pK−48.76
Ca(OH)2Crystalline solid + SO3Liquid
⟶
CaSO4Crystalline solidsoluble, α + 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
−283.94−278.31−18.9–
per 1 mol of
−283.94−278.31−18.9–
per 1 mol of
−283.94−278.31−18.9–
per 1 mol of
−283.94−278.31−18.9–
per 1 mol of
−283.94−278.31−18.9–

Changes in standard condition (3)

Reaction of calcium hydroxide and sulfur trioxide
◆
ΔrG−273.87 kJ/mol
K9.55 × 1047
pK−47.98
Ca(OH)2Crystalline solid + SO3Liquid
⟶
CaSO4Crystalline solidsoluble, β + 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
−279.50−273.87−18.9–
per 1 mol of
−279.50−273.87−18.9–
per 1 mol of
−279.50−273.87−18.9–
per 1 mol of
−279.50−273.87−18.9–
per 1 mol of
−279.50−273.87−18.9–

Changes in aqueous solution (1)

Reaction of calcium hydroxide and sulfur trioxide
◆
ΔrG−286.22 kJ/mol
K1.39 × 1050
pK−50.14
Ca(OH)2Crystalline solid + SO3Crystalline solidβ
⟶
CaSO4Crystalline solidinsoluble, anhydrite + 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
−279.34−286.2222.5–
per 1 mol of
−279.34−286.2222.5–
per 1 mol of
−279.34−286.2222.5–
per 1 mol of
−279.34−286.2222.5–
per 1 mol of
−279.34−286.2222.5–

Changes in aqueous solution (2)

Reaction of calcium hydroxide and sulfur trioxide
◆
ΔrG−277.85 kJ/mol
K4.76 × 1048
pK−48.68
Ca(OH)2Crystalline solid + SO3Crystalline solidβ
⟶
CaSO4Crystalline solidsoluble, α + 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
−270.47−277.8524.2–
per 1 mol of
−270.47−277.8524.2–
per 1 mol of
−270.47−277.8524.2–
per 1 mol of
−270.47−277.8524.2–
per 1 mol of
−270.47−277.8524.2–

Changes in aqueous solution (3)

Reaction of calcium hydroxide and sulfur trioxide
◆
ΔrG−273.41 kJ/mol
K7.93 × 1047
pK−47.90
Ca(OH)2Crystalline solid + SO3Crystalline solidβ
⟶
CaSO4Crystalline solidsoluble, β + 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
−266.03−273.4124.2–
per 1 mol of
−266.03−273.4124.2–
per 1 mol of
−266.03−273.4124.2–
per 1 mol of
−266.03−273.4124.2–
per 1 mol of
−266.03−273.4124.2–

Thermodynamic data of reactants

Chemical formulaStandard 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
Ca(OH)2 (cr)-986.09[1]-898.49[1]83.39[1]87.49[1]
Ca(OH)2 (g)-544[1]–––
Ca(OH)2 (ai)-1002.82[1]-868.07[1]-74.5[1]–
Ca(OH)2 (cr)
2 hydrate
-1218.4[1]–––
SO3 (cr)
β
-454.51[1]-374.21[1]70.7[1]–
SO3 (l)-441.04[1]-373.75[1]113.8[1]–
SO3 (g)-395.72[1]-371.06[1]256.76[1]50.67[1]
* (cr):Crystalline solid, (g):Gas, (ai):Ionized aqueous solution, (l):Liquid

Thermodynamic data of products

Chemical formulaStandard 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
CaSO4 (cr)
insoluble, anhydrite
-1434.11[1]-1321.79[1]106.7[1]99.66[1]
CaSO4 (cr)
soluble, α
-1425.24[1]-1313.42[1]108.4[1]100.21[1]
CaSO4 (cr)
soluble, β
-1420.80[1]-1308.98[1]108.4[1]99.04[1]
CaSO4 (ai)-1452.10[1]-1298.10[1]-33.1[1]–
CaSO4 (cr)
0.5 hydrate
macrocrystalline, α
-1576.74[1]-1436.74[1]130.5[1]119.41[1]
CaSO4 (cr)
0.5 hydrate
microcrystalline, β
-1574.65[1]-1435.78[1]134.3[1]124.22[1]
CaSO4 (cr)
2 hydrate
selenite
-2022.63[1]-1797.28[1]194.1[1]186.02[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

  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)