Sulfur

Question 1

What are sources of sulfur

Answer 1

• In elemental state underground
• By-product from the removal of sulfur from petroleum and natural gas
• Sulfide ores

Question 2

Uses of sulfur

Answer 2

• Making sulphuric acid
• Making rubber tyres more flexible, by heating them with sulfur

Question 3

How is sulphur dioxide made

Answer 3

Question 4

Uses of sulphur dioxide

Answer 4

• A bleach in the manufacture of wood pulp
• A preservative for food and drinks by killing bacteria
• Sulfites are added to food to release sulphur dioxide in acidic conditions

Question 5

What proccess synthesizes sulphuric acid

Answer 5

The contact process

Question 6

First stage of the contact process

Answer 6

Sulphur is oxidised

Question 7

Second stage of the contact process

Answer 7

Sulphur dioxide is oxidised to suplhur trioxide in the presence of a V₂O₅

Question 8

What are the conditions for the second stage of the contact process

Answer 8

450*C

2 atm. pressure

Question 9

Why must the tempurature be 450* in the oxidation of SO₂

Answer 9

• The reaction is exothermic, increasing the tempurature shifts equilibrium to the left (reactants)
• The higher the tempurature the lower the yield therefore

Question 10

Why is there 2 atm. of pressure in the second stage of the contact process

Answer 10

• It is not worth spending the extra energy or money on higher pressures
• A higher pressure would increase the problems of dealing with high pressures of dealing with corrosive mixtures of gas

Question 11

What is the third stage of the contact process

Answer 11

• Sulfur trioxide is abosrbed into a 98% solution of H₂SO₄
• This forms oleum H₂S₃O₇
• Oleum is then reacted with water to produce to form concentrated H₂SO₄

Question 12

Properties of sulphuric acid

Answer 12

• Strong dibasicacid - two of its atoms can be replaced by a metal
• Reacts in a similiar way to other acids with metal carbonates
• Corrosive
• Powerful oxidising agent

e.g. glucose mixed with sulphuric aicd will remove water molecules and leave behind a tower of pure carbon

Question 13

Uses of dilute sulphuric acid

Answer 13

• Cataylst in organic reactions
• Also used to clean the surface of metals

Question 14

Uses of concentrated sulphuric acid

Answer 14

• Making car batteries
• phosphate fertilizers
• soaps and detergants
• Used to make acid drain cleaners
• used in the production of paints and dyes