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Chemistry > C3 - Chemicals in our Lives - Risks and Benefits > Flashcards

C3 - Chemicals in our Lives - Risks and Benefits Flashcards

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1
Q

What are the four layers of the Earth?

A
  • Crust
  • Mantle
  • Outer core
  • Inner core
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2
Q

tectonic plates

A

Massive portions of rock which make up the Earth’s surface

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3
Q

Convection currents

A

Small currents which move the tectonic plates around the earth

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4
Q

Name the ways the plates can move:

A

•By sliding past each other, colliding or pulling apart

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5
Q

Pangea

A

The supercontinent which all the continents used to be

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6
Q

Rocks

A

Raw materials found in the Earth’s crust

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7
Q

Name 3 important raw materials

A

Coal, salt and limestone

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8
Q

How is limestone made? 4 steps

A
  • Shellfish died forming sediments on the sea bed
  • Sediments compacted and hardened to form limestone, a sedimentary rock
  • Tectonic plate movements pushed the rock to the surface
  • Gradually the rocks above were eroded away until the limestone was exposed
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9
Q

How is coal made?

A

It is formed in wet, swampy conditions when plants like trees and ferns died and became buried. This excluded oxygen slowing decay.

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10
Q

How is salt made? 3 steps

A
  • Rivers brought dissolved salts into the sea
  • Climate warming evaporated the water, leaving salt that mixed with sand blown in by the wind
  • Rock salt formed and was buried by other sediments
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11
Q

What evidence is there for the formations of limestone, coal and salt?

A
  • Coal contains fossils of the plants that formed it
  • Limestone contains bits of shell fragments from sea creature
  • Rock salt contains different shaped water and wind eroded grains
  • Ripple marks in rocks from water flow from rivers or waves in the sea
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12
Q

Two uses of salt

A
  • Food
  • As a source of chemicals
  • To treat icy roads
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13
Q

What is salts chemical name?

A

Sodium chloride (NaCl)

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14
Q

How can salt be obtained?

A
  • Collecting and evaporating sea water

* Mining underground deposits of rock salt

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15
Q

Why is rock salt spread on icy roads?

A
  • The rock is insoluble but the sand in the rock salt gives grip
  • It shows up so people know when roads have been gritted
  • The salt in solution lowers the freezing point, preventing ice forming as easily
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16
Q

Where is Britain’s only salt mine?

A

Cheshire

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17
Q

Where can coal be sourced in the UK?

A

South Lancashire

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18
Q

Where can limestone be sourced in the UK?

A

The Peak District

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19
Q

How is solution mining carried out?

A
  • Water is pumped at high pressure into the rock salt
  • The salt dissolves
  • The salt solution is pushed to the surface
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20
Q

Subsidence

A

When land collapses due to weak support underground

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21
Q

3 issues with solution mining:

A
  • It causes subsidence
  • It can allow water into mines which may let salt leach out into water supplies, contaminating them
  • Evaporating salt from sea water takes up large areas and spreads salt into the local environment, damaging habitats
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22
Q

Two ways how salt is used in food

A

As a flavouring and a preservative

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23
Q

Three health problems which high salt intake can cause:

A
  • High blood pressure
  • Heart failure
  • Strokes
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24
Q

Risk

A

The chance of getting ill and the consequences if you did

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25
Q

What do the DH and the DEFRA stand for and what do they do?

A

The Government department of health and the department of the environment, food and rural affairs are responsible for carrying out risk assessment for chemicals in food and advising the public about how food affects health.

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26
Q

Alkalis

A

Compounds which dissolve to give a solution with a pH higher than 7

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27
Q

Neutralisation

A

When alkalis neutralise acids to make salt

28
Q

What is the word equation for neutralisation

A

Acid + Base (Hydroxide) -> Salt + Water

29
Q

What are the uses of alkalis?

A
  • Dyeing cloth
  • Neutralising acidic soil
  • Making soap
  • Making glass
30
Q

What substances were used in the past as sources of alkalis?

A

Stale urine and ash from burnt wood

31
Q

What was soap made of?

A

Wood ashes, animal fat and water

32
Q

What was neutral soil made of?

A

Seaweed, seaweed ashes and lime (calcium oxide)

33
Q

Soda

A

Seaweed or seaweed ash

34
Q

Lime

A

Calcium oxide

35
Q

What is the actual chemical equation for limestone

A

Calcium carbonate

36
Q

What was glass made of?

A

Lime, sand and seaweed

37
Q

How was cloth dyed before?

A

Using plant dye and alum

38
Q

Alum

A

Stale urine

39
Q

Who discovered how to make an alkali in 1787?

A

Nicholas Leblanc

40
Q

What did the Leblanc process do?

A

Made sodium carbonate by reacting salts and limestone heated with coal

41
Q

What are the waste products of The Leblanc process?

A

Sodium carbonate, hydrogen chloride and galligu

42
Q

What is problematics about hydrogen chloride and galligu?

A

Hydrogen chloride contributes towards acid gas and rain and Galligu slowly releases hydrogen sulphide a foul smelling, toxic gas

43
Q

How is hydrogen chloride used?

A
  • Chlorine used to bleach textiles

* Hydrogen acid which is a starting material for making other chemicals

44
Q

What is the equation for making chlorine from Hydrochloric acid and manganese dioxide?

A

Hydrochloric acid + Manganese dioxide -> Chlorine + Manganese chloride + Water

45
Q

Name 3 soluble hydroxides

A

Sodium hydroxide, potassium hydroxide and calcium hydroxide

46
Q

Name 2 soluble carbonates

A

Sodium carbonate and potassium carbonate

47
Q

Bases

A

Insoluble metal carbonates and metal hydroxide

48
Q

Name 4 neutralisation equations:

A

Acid + Base -> Salt + Water
Acid + Metal Oxide -> Salt + Water
Acid + Metal Carbonate -> Salt + Water + Carbon dioxide
Acid + Metal -> Salt + Hydrogen

49
Q

Why is chlorine added to water supply?

A

To kill microorganisms

50
Q

What are the issues with using chlorine?

A
  • Chlorine gas is toxic and can affect human health in excess
  • Sone people disapprove of adding chlorine to water supplies. People using mains water supplies have no choice about chlorination
  • Chlorine can react with organic materials in water supplies, forming toxic or carcinogenic compounds called disinfectant by products (DBPs)
51
Q

Electrolysis

A

A process which breaks up compounds using an electrical current

52
Q

What are the products of the electrolysis of brine?

A

Chlorine gas, hydrogen gas and sodium hydroxide solution

53
Q

Anode

A

The positive electrode

54
Q

Cathode

A

The negative electrode

55
Q

At which electrodes do chlorine and hydrogen gases form

A

Chlorine at the anode and hydrogen at the cathode

56
Q

What are each of the products of brine electrolysis used for?

A
  • Chlorine for making plasticised PVC, in medicine and crop protection
  • Hydrogen for making margarine, as rocket fuel and in fuel cells in vehicles
  • Sodium hydroxide for paper recycling, industrial cleaners and refining aluminium
57
Q

Risk assessment

A

A vigorous process which analyses the hazards and risks of a process

58
Q

What four things do we need to know to decide the level of risk of a particular chemical?

A
  • How much of it is needed to cause harm
  • The chance of it escaping into the environment
  • How much will be used
  • Who or what it may affect
59
Q

What is PVC

A

A plastic containing carbon, hydrogen and chlorine

60
Q

Plasticisers

A

Small molecules added to plastics to make them softer

61
Q

Uses of plasticised PVC

A

For covering electrical wires, clothing and seat covers

62
Q

LCA

A

A life cycle assessment measures the energy used to make, use and dispose of a substance and it’s environmental impact

63
Q

What are the four stages of an LCA?

A
  1. Preparing the chemical from raw materials found in plants, animals, rocks, the ocean or the air
  2. Making the product from the chemicals including transporting the chemicals and the finished product
  3. Using the product
  4. Disposing of the products and the materials in it when it is of no more use
64
Q

What must be considered during an LCA?

A
  • How much natural resources are required
  • How much energy is needed or required
  • How much water and air is used
  • How is the environment affected
65
Q

Geologists

A

Scientists which study rocks

Chemistry (6 decks)

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