using resources excl water

Question 1

clay ceramics:
1) how made
2) 2 examples

+ what are ceramics

Answer 1

ceramics are non metal solids, high melt points no carbon

1) made by digging up soft, wet clay. this is easily moulded. fired in a furnace at high temperatures, hardens to form clay ceramic.
2) POTTERY AND BRICKS

Question 2

glass (ceramic):
2 types
how each made
common?
difference
use

Answer 2

soda-lime glass; heating limestone, sand, and sodium carbonate until it melts. cools and forms glass. glassware- cups

borosilicate glass: heat a mixture of sand and boron trioxide until it melts. cools and forms glass. less common. higher melting point. test tubes

Question 3

general physical properties of ceramics

Answer 3

glass AND clay:
1) insulators of heat and electricity
2) brittle (hard but not flexible and break easily)
3) stiff

Question 4

composites:
how made
what are they
what do properties depend on

Answer 4

1) made when fibres or fragments of a material (reinforcement) are surrounded by a material known as a matrix acting as a binder. one material embedded

2) materials made up of two materials

3) Their properties depend on the properties of the reinforcement and matrix/binder. properties vary

Question 5

4 examples of composite, reinforcement & matrix, properties, use

Answer 5

1. Fibreglass- composed of fibres of glass embedded in a polymer matrix. low density (plastic), strong (glass) . surfboards
2. carbon fibre- reinforcement is long carbon chains bonded together or carbon nanotubes embedded in a polymer matrix. strong and light so used in racing cars. high strength to weight to ratio
3. concrete- reinforcement of an aggregate (sand or gravel usually) and matrix is cement. strong so used in building material. skate parks
4. wood- natural composite of cellulose fibres as reinforcement surrounded by an organic polymer matrix

Question 6

what do the properties of the polymer depend on + general properties

Answer 6

properties depend on the monomer that they are made from and how they are made.

generally: insulators of heat and electricity, can be flexible and easily moulded

many applications

Question 7

how are low density poly(ethene) LDPE and high density poly(ethene) made.

arrangement of both and melting point

Answer 7

LDPE made from ethene monomers at high pressures, moderate temp and low availability of o2. bags

HDPE from ethene monomers at a lower temperature and pressure + catalyst. hard hats, crates

both thermosoftening

LDPE is flexible, polymer chains are separated therefore intermolecular forces are low so less energy to overcome these, low melting point.

HDPE is rigid as polymer chains are tangled closely together. greater intermolecular forces so more energy to overcome which means it has a higher melting point

Question 8

thermosetting vs thermosoftening polymers

Answer 8

thermosetting: monomers that form cross links between individual polymer chains, holding the polymer in a solid structure. don’t soften and don’t melt when heated, burn. held together by strong covalent bonds (cross links)

thermosoftening: individual polymer chains entwined with other chains, weak intermolecular forces between chains. no cross links just tangled chains. when heated, soften and melt and remould.

Question 9

alloys: explain what happens

Answer 9

mixture of 2 or more metals, one of which is a pure metal

different size metal atoms disrupt metallic lattice, harder for layers to slide over.

harder

most metals in everyday use are alloys

Question 10

3 types of steel: name, properties, uses

iron + carbon

Answer 10

low carbon steel (0.1-0.3%)- easily shaped- car bodies

high carbon steel (0.2-2.5%)- hard, strong, brittle- blades in cutting tools

stainless steel (chromium and nickel added)- corrosion resistant and cutlery, containers

Question 11

alloys:
bronze
brass
gold alloys + carat system
aluminium alloys

metals used, uses

Answer 11

bronze- copper and tin; hard- medals, ornaments and statues

brass- copper and zinc. malleable, taps, instruments

gold alloys- gold + (copper,zinc,silver) hardens. jewellery. 24 carat pure gold. find out % of gold by carat no/24 * 100. 18 carat is 75% gold 18/24 *100.

aluminium alloys- alloyed to harden. aircraft manufacture. aluminium low density which is good for aircraft

Question 12

corrosion:
1) what is it
2) what is rusting and what is needed
3) equation

Answer 12

1) destruction of metals/materials through chemical reactions with their environment. surface of material that is exposed
2) rusting is an example of corrosion. iron only. need air and water.
3) iron + oxygen + water -> hydrated iron oxide

Question 13

rusting in iron vs corrosion in aluminium

Answer 13

when iron rusts, pieces of iron on surface flake away and more iron exposed. all iron eventually corrodes away

aluminium corrodes to form an oxide layer over it. this acts as a protective layer and stops any further corrosion so aluminium remains intact.

Question 14

experiment for rusting + mass change of rusty nail

Answer 14

put an iron nail in a boiling tube. in one boiling tube put boiled water (remove o2) and oil (prevents oxygen coming in), in another test tube add calcium chloride (which will absorb any water from air) and in the final one add water and air.

leave for a week

one with water and air will rust, other 2 will not. mass of rusty nail will increase

Question 15

what is barrier method and 3 ways- corrosion

Answer 15

prevents rusting as iron is coated to keep out h20 and o2.

painting/plastic coat.
electroplating- use electrolysis to reduce metal ions of a different metal that wont be corroded which coats iron.
oiling/greasing- reduce friction on moving parts.

Question 16

what is sacrificial method

Answer 16

placing a more reactive metal such as zinc to galvanise iron. water and oxygen then react with the more reactive metal instead of iron

Question 17

how do humans use Earth’s resources

what do natural resources supplemented by agriculture provide examples

where do finite resources come from and what do they provide examples

natural products that are supplemented or
replaced by agricultural and synthetic products

Answer 17

for warmth, shelter, food, transport

food, timber, clothing, fuels. come from air, sea and earth - cotton. timber, food

come from ocean and atmosphere and provide energy and materials . ores, nuclear fuels (uranium and plutonium) and fossil fuels (coal, oil and gas)

rubber from tree sap replaced by rubber made from polymers (tyre), fertiliser supplements agriculture as higher crop yields.

Question 18

what is sustainable development and how can chemistry help (3)

Answer 18

sustainable
development, which is development that meets the needs of current
generations without compromising the ability of future generations
to meet their own needs.

chemistry can improve agricultural and industrial processes to provide new products like fertilisers developing catalysts which reduce energy input in a chemical reaction + try to reduce waste (biodegradable)

Question 19

earths levels of metal and copper ores

how can copper ores be extracted sustainably

criticism

Answer 19

Earth level of metal ores and copper ores are becoming more scarce

sustainable methods move away from mining and can be done in 2 ways, extract from low grade ore

phytomining: growing plants in soil which contains copper. plants take up copper but don’t use it so copper builds up in leaves. harvested, dried and burned in furnace. ash contain soluble copper compounds, extracted by electrolysis or a displacement reaction with scrap iron/ more reactive metal

bioleaching: bacteria convert copper compounds into leachate solution that contains soluble copper ions, extracted by electrolysis or a displacement reaction with scrap iron/ more reactive metal

slow process

ALSO USED FOR OTHER METALS

Question 20

what is an LCA and 4 stages

Answer 20

Life cycle assessments (LCAs) are carried out to assess the
environmental impact of products in each of these stages:
* extracting and processing raw materials- processed with enerfy
* manufacturing and packaging- transport to centres
* use and operation during its lifetime- poollution released (air, water)- reused?
* disposal at the end of its useful life, including transport and
distribution at each stage (landfill)

Question 21

LCA for paper and plastic bag

Answer 21

**Plastic carrier bags **
**Raw materials **Crude oil is a finite resource;
Manufacture fractional distillation, cracking and polymerisation all require a lot of energy. Cheaper to make large quantities of bags from plastic.
Use Lower impact on the environment because plastic bags are usually stronger so they can be reused many times.
**Disposal **Can sometimes be collected and recycled; if disposed of as litter, they do not biodegrade; in landfill, may take decades or centuries to degrade. pollute land

Paper carrier bags
Raw materials- Can be made from recycled paper, or from trees. Making paper from trees requires more energy than recycling paper, but much less than making plastics. renewable. but deforestation and co2
manufacture- More expensive to make bags from paper because the handles must be glued on. and processing timber = lots of waste
Use- Relatively short lifetime; can only be reused a limited number of times.
**Disposal- ** Can be recycled easily; if disposed of in landfill, they biodegrade quickly. non-toxic

plastic take less energy and have a longer lifespan so may be less harmful to environment

Question 22

issues with LCAs (3)

Answer 22

1. some can be easily quantified with data and numbers like water / waste, but others like pollution can’t
2. LCA subjective as opinioon of assessor is taken into account - not objective
3. selective LCA only show some ipmacts- used to deliberately support a company/organisation

Question 23

what does the reduce, reuse, recycle scheme do
why important

Answer 23

reduces the use of limited resources, use of energy sources, waste
and environmental impacts

metals, glass, clay ceramiccs, polymers and composites and building materials come from limited raw materials from earth. obbtaining these by mining or quarrying causes damage. recyling is less energy intensive as manufacture and conserves resource.

Question 24

how is glass sustainably used

Answer 24

can be re used without reshaping
can be recycled: crushed and melted and reformed to make glass or something else

Question 25

how are metals recycled + scrap steel specific rule

Answer 25

by melting and recasting. the amount of separation required depends on materials and properties of final product

scrap steel can be added into a blast furnace to reduce the amount of iron ore required

Question 26

HABER PROCESS:

purpose
reaction
where reactants sourced from

Answer 26

produce ammonia and ammonia based fertiliser.

N2 + 3H2 ⭇ 2NH3

N2 sourced from air (fractional distillation)
H2 sourced from reacting methane and steam (steam cracking of methane) to form h2 and co2

Question 27

reaction diagram explained for haber

Answer 27

h2 and n2 in
pass over trays of iron catalyst
gas condensed
liquid ammonia collected
unused h2 and n2 are recycled

Question 28

reaction condition for haber link to dynamic equilibrium

Answer 28

1. 450c temp - forward reaction exothermic, so high temp = low yield (equilibrium moves to endothermic direction so more n2 and h2) but high temp = fast ror so compromise at 450.
2. conc of n2 and h2 high as liquid ammonia collected continually and reactants always pumped in
3. 200 atm pressure- high pressure = fast ror and high yield (moves to side with fewest gas molecules NH3) but high pressure dangerous and expensive (need high pressure tank)
4. iron catalyst- alternate pathway lower ea. means lower temp can be used which increase yield. also increase ror

Question 29

what are NPK fertilisers made from and why good

Answer 29

Compounds of nitrogen (protein) , phosphorus (root growth) and potassium are used as fertilisers to improve agricultural productivity. replaces nutrients that have been taken up by previous crop.
better than manure

Question 30

how to produce nitratets for NPK + industrial and lab process

Answer 30

ammonia (haber) + nitric acid -> ammonium nitrate
nh3 + hno3 -> nh4no3

industrial = large vats, high concentration. exothermic reaction. heat released evaporates water from mixture to make ammonium nitrate. ammonia + water + oxygen -> nitric acid. nitric acid + ammonia -> ammonium nitrate.

lab = titration (nh3 and hno3) and crystallisation. lower concentration so safer

Question 31

how are phosphate ions and potassium ions for NPK obtained.what is wrong with source of phosphates

Answer 31

potassium chloride/sulphate mined as a source of potassium ions

phosphate rock (contains phosphorous and calcium) mined- but this is insoluble so plants can’t use them, react with acids to make soluble phosphates.

Question 32

products when phosphate rock reacted with nitric acid, sulfuric acid and phosphoric acid

Answer 32

nitric acid + phosphate rock -> phosphoric acid + calcium nitrate
sulfuric acid + phosphate rock -> calcium sulphate and calcium phosphate single superphosphate
phosphoric acid + phosphate rock -> calcium phosphate- triple spuerphosphate - Ca3(PO4)2