Chemical Equillibrium Content

Question 1

Haber process

Answer 1

200 atm
450•C
Iron catalyst
🔼H=-92 Kj/mol

How to increase rxn rate:
1) Use a suitable catalyst (iron)
2) increase T
3) Increase P
4) maintain high [reactants]

How to increase product yield
1) increase [reactants]
2) decrease T to favour forward rxn
3) increase P to favour forward rxn
4) continually remove NH3 from the system

Uses: making nitric acid (Ostwald)
Detergents, soaps, pigments

Question 2

Contact process

Answer 2

1-2 atm
450•C
V2O5 catalyst
🔼H = -197 Kj/mol

To increase rxn rate:
1) use a suitable catalyst (V2O5)
2) increase T
3) increase P
4) maintain high [reactants]

To increase product yield:
1) increase [reactants]
2) decrease T to favour forward rxn
3) increase P to favour forward rxn
4) continually remove SO3/products

Uses:
SO3 is used to make sulphuric acid used in battery acid, fertilisers, pigments, detergents

Question 3

Ostwald process

Answer 3

300 atm
900•C
Pt/Rh catalyst
🔼H= -900 Kj/mol

To increase rxn rate:
1) use a suitable catalyst
2) increase T
3) increase P
4) maintain high [reactants]

To increase product yield:
1) increase [reactants]
2) decrease T to favour forward rxn
3) decrease P to favour forward rxn
4) continually remove products from system

Uses: fertilisers, plastics, nylon, explosives (nitric acid is used for it)

Question 4

Special considerations for each

Answer 4

Haber and contact:

1) if T is too low, makes rxn very slow, expensive and uneconomical (compromise yield)

2) High P conditions aren’t safe for workers and expensive to maintain

3) left over reactants gasses are recycled to prevent air pollution and make process more economical

Ostwald:
1) low T and P make the reaction very slow and uneconomical

2) T and P values are high to increase rxn rate