1. Title: Lesson 3 Equilibrium and Industry
Learning Objectives:
Review the equilibrium constant experiment from the last lesson
Summarise the impact of equilibrium effects on the Haber Process and the Contact Process
Practise equilibrium exam questions

2. Recap
The diagrams below represent equilibrium mixtures for the reaction Y + X2  XY + X at 350 K and 550 K respectively. Deduce and explain whether the reaction is exothermic or endothermic.
350K K

3. Recap Dynamic Equilibrium and Le Chatelier’s Principle before you move on…
Dynamics and Le Chatelier's Principle Video Recap

4. This lesson… You will be covering Equilibrium and Industry…
Industrial processes you have come across before in IGCSE
The Haber Process
Sulphuric Acid and The Contact Process
Task for this lesson
Read through the slides and watch the videos for ‘The Haber Process’ and ‘The Contact Process’
Fill out the summary sheet for both reactions
Read through the slides on ‘Making Methanol’
Answer the questions on the sheet on Equilibrium and Industry
Complete the SL Equilibrium exam questions

5. Haber Process TedEd Video
= manufacture of ammonia by direct synthesis from nitrogen and hydrogen
N2(g) obtained from atmosphere
H2(g) obtained by thermal cracking of hydrocarbons
N2(g) + 3H2(g) ⇌ 2NH3(g)
; H = -93 kJ mole-1
Le Chatelier’s Principle suggests NH3(g) production is favoured by :
(1) HIGH pressure since 4 mols  2 mols
(2) LOW temperature since forward reaction exothermic
(3) Removal of NH3 to pull equilibrium to the right and increase the yield
In practice, the process carried out at 450C and 20000kPa in the presence of an iron catalyst

6. “Compromise” 450C and 20000kPa used because:
Why not higher?
Why not lower?
Pressure
Temperature
Increased yield and rate but add to costs – pumping energy, structural engineering and safety problems.
Reduced costs (see opposite) but reduced yield and rate
Increased rate but decreased yield and increased energy costs
Reduced energy costs but decreased rate
speeds up the reaction without the need to raise temperature or pressure too much.
IRON catalyst
 acceptable yield and rate with acceptable energy (including CO2 emissions), equipment and safety costs.

7. % AMMONIA in main reaction vessel
HYDROGEN & NITROGEN IN
hydrogen + nitrogen
ammonia
HYDROGEN NITROGEN AMMONIA
UNUSED HYDROGEN & NITROGEN RECYCLED
TEMPERATURE and PRESSURE of the reaction vessel can be controlled
% YIELD =
% AMMONIA in main reaction vessel
Mixture cooled here. AMMONIA condenses
LIQUID
AMMONIA REMOVED

8. Uses of Ammonia
UK annual production: ≈1.3 million tonnes World annual production: ≈140 million tonnes
1. Ammonia is reacted with an acid to form an ammonium salt
e.g. 2NH3(g) + H2SO4  (NH4)2SO = ammonium sulphate
Ammonium sulphate is an essential component of many fertilisers
The ammonia acts as base – accepts a proton from the acid – to form the ammonium ion, NH4+
NH3 + H+  NH4+

9. 2. Ammonia is also used to make nitric acid, HNO3
Nitric acid is an essential reagent for making useful materials such as :
1. POLYAMIDES such as nylon
2. EXPLOSIVES such as TNT and nitroglycerine

10. The Contact Process: Production of sulphuric acid H2SO4
3 simple reactions:
The combustion of sulphur to form sulphur dioxide;
The oxidation of sulphur dioxide to sulphur trioxide:
The combination of sulphur trioxide with water to form sulphuric acid.
Overall rate depends on step (ii). So we apply Le Chatelier’s principle to this step:
2SO2(g) + O2(g) ⇌ 2SO3(g)
; H = -196kJ mole-1

11. Contact Process
= process by which sulphur dioxide, SO2, is converted to sulphur trioxide, SO3, for conversion to sulphuric acid
2SO2(g) + O2(g) ⇌ 2SO3(g)
; H = -196kJ mole-1
 SO3(g) manufacture favoured by:
(a) excess SO2 and / or O2
(b) removal of SO3
(c) LOWER temperature
because exothermic
(d) HIGHER pressure
because 3 mols  2 mols
Sulphuric Acid and The Contact Process RSC Video

12. “Compromise” 450C and 200atm used because:
Why not higher?
Why not lower?
Pressure
Temperature
Increased yield and rate but add to costs – pumping energy, structural engineering and safety problems.
Reduced costs (see opposite) but reduced yield and rate
Increased rate but decreased yield and increased energy costs
Reduced energy costs but decreased rate
speeds up the reaction without the need to raise temperature or pressure too much.
V2O5 (Vanadium (V) oxide) catalyst
 acceptable yield and rate with acceptable energy (including CO2 emissions), equipment and safety costs

13. The importance of sulphuric acid
Uses of sulphuric acid:

14. Equilibrium and Industry
Complete the following table
Haber Process
Contact Process
Reactions and Conditions
Justification of Conditions
Importance of the Process

15. Making Methanol
Carbon monoxide is converted to methanol by reaction with hydrogen at 250°C and (5 to 10) x 106 Pa using copper catalyst
CO(g) + 2H2(g) ⇌ CH3OH(g)
; H = -90kJ mole-1
CO + H2 mixture produced by reacting methane with steam
= “syngas”
 CH3OH(g) manufacture favoured by:
(a) excess CO and / or H2
(b) removal of CH3OH
(c) LOWER temperature
because exothermic
(d) HIGHER pressure
because 3 mols  1 mol

16. Le Chatelier’s principle for optimizing production

17. “Compromise” 250C and (5 to 10) x 106 Pa used because:
Why not higher?
Why not lower?
Pressure
Temperature
Increased yield and rate but add to costs – pumping energy, structural engineering and safety problems.
Reduced costs (see opposite) but reduced yield and rate
Increased rate but decreased yield and increased energy costs
Reduced energy costs but decreased rate
speeds up the reaction without the need to raise temperature or pressure too much.
Copper catalyst
 acceptable yield and rate with acceptable energy (including lower CO2 emissions) and safety costs

19. Solutions

20. Time to Practise Work through the question pack
Answers are at the back

21. Recap Many industrial processes take advantage of equilibrium effects.
Two of the most important are:
Haber process for making ammonia
Contact process for making sulphuric acid