Chap 8 Part 1

CHAP. 8 MANUFACTURED SUBSTANCES IN INDUSTRY 1.0 SULPHURIC ACID AND AMMONIA Learning Outcome 1. Students able to write an equation for CONTACT PROCESS and HABER PROCESS 2. Able to mention the condition of reaction in CONTACT PROCESS and HABER PROCESS. 3. List out the uses of SULPHURIC ACID (H2SO4) and AMMONIA (NH3) 4. Explain how SULPHUR DIOXIDE (SO2) causes environmental pollution. 1.1

SULPHURIC ACID 1.1.2 MANUFACTURED OF SULPHURIC ACID (CONTACT PROCESS)

SULPHUR

OXYGEN

Stage 1 : PRODUCTION OF SO2 Molten sulphur is burnt in excess oxygen (dry air) to produce SULPHUR DIOXIDE. S + O2  SO2

SULPHUR DIOXIDE (SO2)

SULPHUR TRIOXIDE (SO3)

OLEUM (H2S2O7)

SULPHURIC ACID (H2SO4)

By Naguib Zakaria

Stage 2 : PRODUCTION OF SO3 Sulphur dioxide and oxygen are pass through VANADIUM (V) OXIDE (catalyst) to produce SULPHUR TRIOXIDE (SO3) 2SO2 + O2  2SO3 o o Temp: 450 C – 500 C Pressure : 2 – 3 atm Catalyst : vanadium (v) oxide

Stage 3 : PRODUCTION OF H2SO4 SO3 is dissolved in concentrated sulphuric acid to form OLEUM. SO3 + H2SO4  H2S2O7 OLEUM is mix with water (to dilute) to produce concentrated sulphuric acid. H2S2O7 + H2O  2H2SO4

1.1.3 THE USES OF SULPHURIC ACID

Dyes, 2%

Metal Cleaning, 2%

Acid, 2%

Synthetic Fibre, 9%

Fertilisers Fertilisers , 32%

Electrolyte, 10%

Paint Pigment Other Chemicals Detergents Electrolyte Synthetic Fibre Dyes Metall Cleaning Acid

Detergents, 12% Paint Pigment, 15% Other Chemicals, 16%

Fertilisers: A large portion of sulphuric acid is used to manufacture fertilisers such as: Calcium hydrogen phosphate Ammonium sulphate Potassium sulphate

Uses in school laboratories: As a strong acid As a drying or dehydrating agent As an oxidising agent As a catalyst

Detergent: synthetic cleaning agents. Synthetic Fibres: Polymers (long chained molecules), example: Rayon. Electrolyte: use in car batteries

1.1.4 ENVIRONMENTAL POLLUTION SULPHUR DIOXIDE (release from factories or power station) to atmosphere. SO2 dissolves in rain to form sulphurous acid (ACID RAIN) EFFECT OF ACID RAIN Corrodes the building Increasing acidity in lake or pond that can cause aquatic organism die Increasing the acidity of soil. HOW TO PREVENT EFFECT OF ACID RAIN Gas released from factories sprayed with limestone (calcium carbonate)

By Naguib Zakaria

1.2

HABER PROCESS 1.2.1 MANUFACTURE D OF AMMONIA (HABER PROCESS)

1ST STAGE One volume of Nitrogen gas, N2 and three volume of pure dry Hydrogen gas, H2 are compressed to a pressure between 200 – 500 atmosphere

2nd STAGE The gas mixture (N2 and H2) are passed through a powdered iron at temperature of 450-550oC

3rd STAGE The gas mixture (N2 and H2) are passed through a powdered iron at temperature of 450-550oC N2 + 3H2  2NH3 Condition of reaction: Iron as a catalyst, Temp : 450-550oC, Pressure 200 atm

4th STAGE Ammonia gas turned to liquid when the mixture is cooled in condenser. The unreacted N2 and H2 will pump back to reactor and pass through the catalyst again.

By Naguib Zakaria

1.2.1 USES AND PROPERTIES OF AMMONIA

USES OF AMMONIA 1. Manufactured ammonium sulphate, ammonium nitrate and urea. a. Ammonium sulphate 2NH3 + H2SO4  (NH4)2SO4 b. Ammonium nitrate 2NH3 + NH3  NH4NO3 c. Urea 2NH3 + CO2  (NH2)2CO3 + H2O 2. As a cooling agent in refrigerators. 3. As raw material in OSTWALD PROCESS. OSTWALD Process is converted ammonia into nitric acid using PLATINUM as catalyst 4. Can be converted to nitric acid for making explosives. 5. To prevent coagulation of latex 6. Raw material in produce synthetic fiber and nylon

By Naguib Zakaria

PROPERTIES 1. Colourless and Pungent gas. 2. Dissolve in water to form weak alkali. NH3 + H2O  NH4+ + OHPresence of OH- causes ammonia to become alkaline. 3. Change moist litmus paper from red to blue. 4. Neutralise any acid to form ammonium salt React with sulphuric acid to produce AMMONIUM SULPHATE 2NH3 + H2SO4  (NH4)2SO4