CAIE IGCSE Chemistry Sulfur Trioxide Contact Process Conditions

Practise recalling the temperature, pressure and catalyst for sulfur trioxide manufacture and writing the balanced reversible Contact process equation.

Exam points

state about 450 °C, 200 kPa or two atmospheres and vanadium(V) oxide catalyst
write the reversible balanced equation with two sulfur dioxide and oxygen forming two sulfur trioxide
include units and distinguish the Contact process conditions from those used in the Haber process

[Maximum number: 3]

Sulfur is an important element.

Sulfuric acid is manufactured by the Contact process. One step in the Contact process involves a reversible reaction in which sulfur trioxide, $\mathrm{SO}_{3}$ , is formed.

State the conditions and name the catalyst used in this reversible reaction. temperature
pressure
catalyst

M1 $450^{\circ} \mathrm{C}$ (units required)

M2 1-5 atmospheres (units required)

M3 Vanadium (V) oxide or vanadium pentoxide or $\mathrm{V}_{2} \mathrm{O}_{5}$

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6.3.10—Typical conditions for the conversion question 1