C15 - Haber process

Question 1

haber process

Answer 1

used to manufacture ammonia
- for nitrogen fertiliser

Question 2

haber process materials

Answer 2

hydrogen
nitrogen

Question 3

hydrogen from

Answer 3

natural gas

Question 4

nitrogen from

Answer 4

air

Question 5

Haber process steps

Answer 5

• purified gases are passed over iron catalyst at high temp + pressure
• react to form ammonia
  -ammonia is removed by cooling gases = liquifies
• separated from unreacted gases
• recycled into reaction mixture
• recompressed/heated before returning to reaction vessel

Question 6

reversible reaction - H2 + N2

Answer 6

• some ammonia produced breaks down

Question 7

nitrogen gas costs

Answer 7

-free from air
-costs to separate from other gases (fractional distillation)
- cooling process air must be pressurised - expensive pumps

Question 8

hydrogen obtained by

Answer 8

• react methane with steam at high temps

Question 9

hydrogen costs

Answer 9

water = cheap
- heating is expensive
-methane = expensive

Question 10

effect of pressure of haber process

Answer 10

-volume of reactants > products
- favours forward reaction

Question 11

max ammonia yield

Answer 11

• colder temps
  -max pressure

Question 12

high pressure costs

Answer 12

expensive vessels

Question 13

pressure in haber process

Answer 13

uses 200 atmospheres
- reduces cost but reasonable yield

Question 14

effect of temp on haber process

Answer 14

forward reaction = exothermic
- lower temps favours forward

Question 15

temp used in haber process

Answer 15

450 .c

Question 16

too cold temps con in haber process

Answer 16

rate of reaction is slowed = less frequent collisions of gas
- must be quick = economical
- reduces effect of iron catalyst

Question 17

iron catalyst

Answer 17

• speeds up both reaction
• doesn’t affect yield
• speeds up rate of production to be economical

Question 18

ammonia purpose

Answer 18

to make nitric acid

Question 19

nitric acid purpose

Answer 19

reacts with more ammonia
-makes ammonium nitrate fertiliser

Question 20

ammoinia is an acid or alkali

Answer 20

alkali

Question 21

neutralisation of ammonia - sulfuric acid

Answer 21

ammonium sulfate fertiliser

Question 22

neutralisation of ammonia - phosphoric acid

Answer 22

-ammonium phosphate fertiliser

Question 23

acids used to neutralise ammonia

Answer 23

sulfuric
phosphoric

Question 24

NPK fertilisers

Answer 24

contain formulation of compounds to provide all 3 elements
- to improve agriculture
-nitrogen, phosphorus, potassium

Question 25

source of phosphorus

Answer 25

phosphorus rock -mined

Question 26

source of nitrogen

Answer 26

haber process

Question 27

why can't phosphorus rock be used directly on soil

Answer 27

it is insoluble

Question 28

phosphate rock is treated with

Answer 28

- nitric acid - sulfuric acid - phosphoric acid

Question 29

phosphate rock and nitric acid

Answer 29

-phosphoric acid + calcium nitrate - then phosphoric acid is neutralised with ammonia = ammonium phosphate

Question 30

phosphate rock and sulfuric acid

Answer 30

single superphosphate (calcium phosphate) and calcium sulfate

Question 31

superphosphate

Answer 31

calcium phosphate

Question 32

phosphate rock and phosphoric acid

Answer 32

calcium phosphate triple superphosphate

Question 33

potassium

Answer 33

-potassium salts are mined - eg potassium chloride or sulfate

Question 34

potassium pro

Answer 34

soluble -just separated from impurities the used

Question 35

Temp - Industrial vs Lab Haber Process

Answer 35

I - 450.c L - room temp and bunsen burner

Question 36

equipment and process - Industrial vs Lab Haber Process

Answer 36

I - expensive chemical plant machinery + continuous process L - cheap + batch process

Question 37

Industrial vs Lab Haber Process - starting materials

Answer 37

I - raw materials L - cheap supplier bought

Question 38

Industrial vs Lab Haber Process - scale/yield

Answer 38

I - large and quickly L - small and slowly

Question 39

Industrial vs Lab Haber Process - running costs

Answer 39

I - low labour costs = machines L - labour intensive and high running costs

Question 40

Industrial vs Lab Haber Process - reactant concentration

Answer 40

I - high concentrations + very exothermic L - less so less heat given off

Question 41

Industrial vs Lab Haber Process - separation of product

Answer 41

I - heat produced evaporates water - from reaction mixture - makes concentrated ammonium nitrate L - crystallisation = slow