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Chemistry Paper 2 > Using Resources Haber Stuff Continued (Unit 10) > Flashcards

Using Resources Haber Stuff Continued (Unit 10) Flashcards

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1
Q

What is the Haber Process?

A

Process of making ammonia

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2
Q

What is the word formula for the Haber process?

A

Nitrogen + Hydrogen ⇌ Ammonia

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3
Q

What is the symbol equation for the Haber process? Give state symbols and exo/endo direction

A

N2(g) + 3H2(g) ⇌ 2NH3 (g)

Forward is exothermic, backward is endothermic

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4
Q

Where do you get the reactant gases from?

A

Nitrogen from the air

Hydrogen from methane

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5
Q

What is ammonia useful for?

A

Ammonia-based fertilisers

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6
Q

How is ammonia made in industry?

A

1) gases are heated and vaporised and put through a COMPRESSOR with the conditions mentioned
2) Gaseous mixture is put through a REACTION CHAMBER with the catalyst
3) The gaseous mixture passes through a condenser. Only ammonia condenses as it condenses at highest temperature
4) Liquid ammonia is REMOVED (do you know why?)
5) The unreacted nitrogen and hydrogen is recycled

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7
Q

What are the conditions used in the industry making of Haber process? say in general terms too

A

200 atm (NOT atmospheric pressure)
450°C
Iron catalyst
High pressure, MEDIUM temperature

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8
Q

Which side has more moles in the Haber process?

A

Reactant as has 4 moles (remember to add moles)

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9
Q

Why is there high pressure used?

A

1) increases RATE OF REACTION because more particles per unit volume of gas, so more freq. succ. conditions
2) increased YIELD as equilibrium shifts to the right to decrease pressure (favours side with less moles). More product and less reactant so more yield

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10
Q

Why is the increase in temperature used?

A

Higher rate of reaction is more important than yield as overall more product is formed quicker

2) increases RATE OF REACTION as particles have more KE so more freq. succ. collisions
3) decrease yield as endothermic reaction favoured therefore less product made so less YIELD

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11
Q

How does the recycling of the reactant gases and the REMOVAL of the liquid ammonia affect yield and rate?

A

Increases YIELD
For the removing ammonia, it shifts equilibrium to right to negate for loss of ammonia
No effect on RATE

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12
Q

What compromise has been made for the temperature chosen in the industrial Haber process?

A

Compromise between yield and rate of reaction

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13
Q

What are NPK fertilisers?

A

Nitrate, phosphate, potassium

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14
Q

Why are these fertilisers needed?

A

The mineral ions from plants aren’t restored into the soil as the plants are harvested by farmers.

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15
Q

Why are the minerals in the form of ions?

A

They become soluble which allows plants to absorb them

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16
Q

How are these ions made?

A

By reacting with ammonia!

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17
Q

What is the formula for phosphoric acid?

A

H3PO4

18
Q

What is the formula for nitric acid?

A

HNO3

19
Q

The ions come in the form of SALTS. What are the word equations for making these ammonium salts?

A

Ammonia + nitric acid —> ammonium nitrate

Ammonia + phosphoric acid —> ammonium phosphate

Ammonia + sulfuric acid —> ammonium sulfate

20
Q

Why aren’t ammonium salts made with potassium?

A

All potassium salts are soluble anyway e.g. potassium chloride, potassium sulfate

21
Q

What is the formula for ammonium nitrate?

A

NH3NO4

22
Q

What is the formula for ammonium phosphate?

A

(NH4)3 PO4

23
Q

What is the formula for ammonium sulfate?

A

(NH4)2 SO4

24
Q

What type of reaction is making the ammonium salts?

A

Neutralisation reaction

25
Q

Is ammonia a base, acid, or an alkali?

A

Alkali

26
Q

What is the definition of a salt?

A

A metal OR ammonia reacting with an acid (since ammonia is alkali)

27
Q

If this is a neutralisation reaction for making ammonium salts, why isn’t water produced?

A

The Hydrogen is used in making the NH3 to NH4 because ammonia AS AN ION is NH4+

28
Q

What type of nutrients are NPK?

A

Macronutrients

29
Q

What are the mineral ions in NPK useful for in plants?

A

NitrATE ions are for green foliage
PhosphATE ions make roots strong
Potassium ions are for healthy growth

30
Q

There is an issue here that we can make the phosphate fertilisers only from reacting stuff with phosphate rock. Where do we get it from?

A

From MINING

31
Q

Why can’t we just use phosphate rock for the plants?

A

It is INSOLUBLE

32
Q

How do we get the ammonium phosphate salts?

A

1) phosphoric rock + nitrate acid —> phosphoric acid

Phosphoric acid + ammonia —> ammonium phosphate

33
Q

Alternatively we can make phosphate fertilisers. How do we do this?

A

Phosphate rock + sulfuric acid —> single superphosphate

Phosphate rock + phosphoric acid —> triple superphosphate

34
Q

What is single superphosphate made up of?

A

Calcium phosphate and calcium sulfate

35
Q

What is triple phosphate made up of?

A

Calcium phosphate

36
Q

How does catalyst affect rate and yield?

A

Increases RATE, no effect YIELD

37
Q

Is the Haber process the general name for making ammonia or is it the name for the industrial process?

A

It’s he name for the industrial process

38
Q

Define fertiliser

A

Chemical or natural substance added to soil or land to improve growth of plants

39
Q

How do you make fertilisers in the lab?

A

Ammonia + sulfuric acid —> ammonia sulfate

1) Add 25cm ³ of ammonia to a conical flask
2) Fill a burette with sulfuric acid to the brim where it says 0
3) Open the tap to add acid to the flask, swirling regularly
4) using a glass rod, test the drop of the solution with litmus paper or phenolphthalein indicator until you see a colour change (neutralisation)
N.B do this out the flask so don’t contaminate solution
5) record final burette reading
6) Heat solution to get crystals

40
Q

Compare lab process of making fertiliser vs industrial process.

A

Lab is SMALL scale (e.g. 25cm³)
- industrial is LARGE SCALE (tonnes)
Lab is safe as dilute acid/alkali concentrations are used
- risk if EXPLOSION in industry AND dangerous chemicals used/concentrated
Lab uses glass pipette and burette
- industry uses stainless steel pipes and vessels
Lab reaction is at room temperature
- industry has high temperature AND pressure
Lab process uses titration and crystallisation
- industry sprays conc. sulfuric acid into ammonia gas

41
Q

In terms of commercially used conditions for specific RAW MATERIALS and ENERGY SUPPLIES, how and why has industry adapted to these factors?

A

Hydrogen and ammonia is recycled as it is expensive to extract/finite
Also this leads into energy CONSUMPTION and therefore COST

Chemistry Paper 2 (10 decks)

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