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Flashcards in Contact Process Deck (11):

What 3 raw materials are needed to make sulfuric acid?



What is the Contact process?

Industrial process to make sulfuric acid


What is Stage 1 of the contact process?

Sulfur burns in air to produce sulfur dioxide


What is Stage 2 of the contact process?

Sulfur dioxide and oxygen react to produce sulfur trioxide


What are the conditions chosen for Stage 2 of the contact process?

Pressure = 2 atmospheres (200kPa)
Temperature = 450 degrees
Catalyst = Vanadium Oxide Catalyst


What happens in Stage 3 of the contact process?

Sulfur trioxide is converted to Sulfuric Acid


What factors determine the pressure conditions chosen for the reaction in Stage 2?

3 mol of gas on left
2 mol of gas on right
If pressure is increased, equilibrium position moves to right and yield increases
However, in this reaction, equilbrium position is already too far to the right, no need for high pressures, 2 atmospheres is just enough to push gases through converter


What factors determine the temperature conditions chosen in the Stage 2 reaction?

Forward reaction = exothermic
Backward reaction = endothermic
If temp. increased, yield decreases
High yield favoured by low temp.
Compromise temp. chosen (also catalyst only works above 380 degrees)


How is Stage 3 of the contact process hazardous?

It would produce a very hazardous acidic mist


How are the Hazards of Stage 3 overcome?

Stage 3 is carried out in 2 steps


What are the 2 steps of Stage 3?

Sulfur Trioxide passed through concentrated Sulfuric Acid to make Oleum
Oleum is added to water and reaction makes larger volume of concentrated sulfuric acid