Resources

Question 1

Sustainable / renewable resources

Answer 1

Meets the needs of current generations without compromising the ability of future generations to meet their own needs

Question 2

What is potable water?

Answer 2

Water which is safe for human consumption, and which has sufficiently low levels of dissolved salts and microbes and a pH between 7.5 and 8.5

Question 3

How is most potable water in the UK produced?

Answer 3

• Choosing source
• Passing through filter beds
• Sterilisation

Question 4

How is water made potable? (detailed)

Answer 4

• Filter out big things (eg. Sticks) with a wire mesh
• Use sand beds and gravel to filter out finer particles
• Sterilise it (through bubbling chlorine through it, exposing it to UV light or exposing it to ozone)

Question 5

Benefits and negatives of surface water

Answer 5

• Easy to access
• Replenished frequently
• Can dry up in sun

Question 6

Desalination

Answer 6

• Used to extract potable water from sea-water
• Unlimited because it is from the sea
• However requires huge amounts of energy, lots of energy
• Distillation involves simple distillation but larger quantities
• Collect water vapour and condense it to produce potable water
• Reverse osmosis involves salty water being passed through a membrane
• Only allows water molecules to pass through, so all the larger ions and molecules are trapped, leaving pure and distilled water behind for drinking because it is POTABLE

Question 7

How to treat sewage water?

Answer 7

• Screening and Grit removal
• Sedimentation to produce sewage sludge and effluent
• Anaerobic Digestion of sewage sludge
• Aerobic digestion of effluent (biological treatment)

Question 8

COpper

Answer 8

Copper stores are running out, so we have to extract copper from low-grade ores

Phytomining, bioleaching

They avoid mining, digging and moving or disposing of large rock

Question 9

What is Phytomining?

Answer 9

Phytomining uses plants to absorb metal compounds through their routes

The plants are then harvested and burned to produce ash containing the metal compounds

High concentration of metal ion in tissue, thus also in the ash

Question 10

Bioleaching

Answer 10

Uses bacteria to produce LEACHATE solutions that contain metal compounds

Bacteria is mixed with the low-grade ore

Bacteria carries out a chemical reaction

Question 11

How is copper etractedf?

Answer 11

After bioleaching or phytomining, the leachate/ product needs to have the metal extracted from it

Copper can be displaced from the ore using iron

Iron is more reactive than copper so can be displaced

Scrap ion is used because it is cheap

Copper can also be extracted by electrolysis

Question 12

Key points about bioleaching and phytomining

Answer 12

Both of these allow us to economically extract metals from low-grade ores

They do not require digging or transporting of rock

Question 13

What is the Haber process

Answer 13

The production of AMMONIA

Which can be used for FARMING

Question 14

Equation of Haber Process

Answer 14

N2 + 3H2 2NH3

Question 15

Sources of hydrogen and Nitrogen?

Answer 15

• Hydrogen from the AIR

- Nitrogen from reacting METHANE with STEAM

Question 16

How does the haber process work?

Answer 16

Passing purified Hydrogen and Nitrogen over an IRON CATALYST at around 450 degrees celsius and 200 atmospheres pressure

Hydrogen and Nitrogen reacts to form ammonia.

Reversible reaction, so some of the ammonia cools down and breaks back into nitrogen and hydrogen

To increase the yield, the ammonia is cooled and turned into a liquid when it is
removed

Unreacted nitrogen and hydrogen is recycled back over the iron catalyst

Temperature and pressure is optimal for the shifting of the equilibrium and economic cost when making the yield of ammonia as great as possible.

Low temp increases yield because it is exothermic, but low temperatures slow rate of reaction so it is COMPROMISED at 450 degrees celsius.

IRON CATALYST INCREASES THE RATE OF REACTION

High pressure shifts equilibrium to the products side, increasing its yield, but high pressure is costly and dangerous to work with high pressures. So is temperature.

Question 17

NPK fertilisers

Answer 17

Nitrogen
Potassium
Phosphorus

Improve agricultural productivity (larger plants and faster growing)

NPK fertilisers are formulations of different salts

These salts contain the required elements in the percentages needed by the plants

Question 18

Compounds in NPK Fertilisers and their production

Answer 18

We use AMMONIA and react it with NITRIC ACID to form AMMONIUM NITRATE which is the main compound in NPK fertilisers

Potassium in NPK fertilisers comes from salts potassium chloride or potassium sulphate. BOTH MINED DIRECTLY FROM THE GROUND AND DO NOT NEED FURTHER PROCESSING.

Phosphate rock has to be chemically processes before being used in fertilisers

Question 19

Treating Phosphorus with Nitric Acid

Answer 19

Treating Phosphate rock with NITRIC ACID produces PHOSPHORIC ACID and CALCIUM NITRATE

Phosphoric acid contains phosphorus but we cannot use this directly on plants, so it is NEUTRALISED with AMMONIA

Then Ammonium Phosphate is used in NPK fertilisers

Question 20

Treating Phosphorus with Sulphuric Acid

Answer 20

• Mixture of calcium Phosphate and calcium Sulphate

- This is called SINGLESUPERPHOSPHATE and can be used in NPK fertilisers

Question 21

Treating Phosphorus with phosphoric Acid

Answer 21

• Forms Triple superphosphate

- Which can be used in NPK fertilisers

Question 22

In a school Lab or Industry we produce ammonium nitrate by…

Answer 22

School Lab

• Using dilute solutions of ammonia and nitric acid
• This is to make them safe to work with
• Crystals produced using a water bath and a bunsen burner, requiring a lot of heat energy
• Batch process, not much produced per time

Industry

• Ammonia is used as a gas
• Nitric acid is concentrated
• much more dangerous as the reaction is very exothermic an the heat has to be safely removed and used in later stages
• This heat can be used for evaporation
• Chemicals are produced by a continuous process, so more can be produced more easily