Chemistry in Society

Question 1

what can slag be used for

Answer 1

foundation for buildings or roads

Question 2

list three useful properties of aluminum

Answer 2

has a low density
resistant to corrosion because of its passive oxide coating
relatively strong when alloyed

Question 3

list three uses of aluminum

Answer 3

kitchen foil
drink cans
high voltage electricity cables

Question 4

what do you call iron that comes out of a blast furnace, and why is it useless

Answer 4

pig iron

96% iron because of impurities, making it brittle and soft

Question 5

what can low carbon steel be used for

Answer 5

soft and ductile, used for car body manufacture

Question 6

what can high carbon steel be used for

Answer 6

hard, used for knives and tools

Question 7

what can stainless steel be used for and why

Answer 7

cutlery because it doesn’t rust

Question 8

what is the use of refinery gases

Answer 8

bottled gas eg camping gas

Question 9

what is the use of gasoline

Answer 9

petrol for motor vehicles

Question 10

what is the use of kerosene

Answer 10

jet fuel

Question 11

what is the use of diesel oil

Answer 11

diesel fuel for cars

Question 12

what is the use of fuel oil

Answer 12

oil powered central heating system

Question 13

what is the use of bitumen

Answer 13

road making

Question 14

describe the trend in boiling point and viscosity of the main fractions

with increasing boiling point….

Answer 14

• boiling point increases - larger intermolecular attractions, more energy needed to separate hydrocarbon molecules
• liquids become less volatile - larger molecules evaporate more slowly because there are stronger intermolecular attractions
• liquids are more viscous - greater intermolecular attractions
• burn less easily

Question 15

what does the high temperature in car engines allow to happen?

Answer 15

nitrogen and oxygen from the air react, form nitrogen oxides
react with hydrocarbons to form PHOTOCHEMICAL smog
leads to poor air quality and respiratory diseases

Question 16

what conditions are needed for cracking

Answer 16

600-700C, silica or alumina catalyst

Question 17

what is the use of polypropene

Answer 17

ropes, plastic crates

Question 18

what is the use of polychloroethene

Answer 18

drainpipes, clothing, electrical insulation

Question 19

why are addition polymers hard to dispose of

Answer 19

they are inert due to the strength of the c-c bonds; not biodegradable

Question 20

describe the reactions taking place in the blast furnace

Answer 20

1. Coke burns in a blast of hot air, CO2 is formed and lots of heat
   C+O2 –> CO2
2. The hot CO2 rises up in the furnace and reacts with more coke to form carbon monoxide
   CO2+C–> 2CO
3. Carbon monoxide is the main reducing agent for removing oxygen from the iron oxide, forming molten iron that runs to the bottom of the furnace
   Fe2O3 + 3CO –> 2Fe+3CO2
4. Limestone decomposed to calcium oxide and reacts with acidic impurities like sand and clay, to form slag. This floats on the iron as it is less dense
   CaCO3–> CaO + CO2
   CaO + SiO2 –> CaSiO3

Question 21

list three uses of chlorine

Answer 21

making bleach;
sterilizing drinking water;
making hydrochloric acid

Question 22

list three uses of sodium hydroxide

Answer 22

making bleach;
making soap;
making paper

Question 23

list three uses of chlorine

Answer 23

making bleach;
sterilizing drinking water;
making hydrochloric acid

Question 24

list three uses of sodium hydroxide

Answer 24

making bleach;
making soap;
making paper