Alkanes

Question 1

what are the products of complete combustion?

Answer 1

CO2 + H2O

Question 2

what are the products of incomplete combustion

Answer 2

CO(g) + H2O
or

C(s) +H2O

Question 3

pollutants from complete combustion

CO2
H2O

Answer 3

-greenhouse gases results in global warming

Question 4

what is the greenhouse effect?

Answer 4

-UV wavelength radiation passes through the atmosphere to the Earth’s surface and heats up Earth’s surface.

-Earth radiates out infrared long wavelength radiation

Question 5

pollutants from incomplete combustion

Answer 5

-carbon monoxide- toxic
-Soot: leads to global dimming and respiratory problems
Unburnt hydrocarbons : smog

Question 6

what is a product if an organic compound contains sulphur

Answer 6

SO2(g)

Question 7

what is a product if an organic compound contains nitrogen

Answer 7

NO(g)

Question 8

what are any unwanted organic compounds found in fuels called?

Answer 8

impurities

Question 9

what is the problem of sulphur dioxide in the atmosphere

Answer 9

causes respiratory issues
-acid rain : makes soil more acidic: harder for crops to grow, makes lakes more acidic harming aquatic animals

Question 10

how can chemistry reduce the amount of sulfur dioxide released into the atmosphere

b) equation

Answer 10

-by passing them through a scrubber which contain solid calcium oxide which reacts with the sulfur dioxide in a neutralisation reaction

b) SO2 + CaO–> CaSO3

Question 11

what pollutant can a petrol engine produce via comnustion

Answer 11

soot
water vapour
unburnt hydrocarbon

Question 12

what is the problem of nitric oxide in the atmosphere

Answer 12

acid rain
respiratory issues

Question 13

write the equation which represents the reaction nitrogen undergoes in an engine

b) conditions needed for this reaction to occur

Answer 13

N2(g) + O2(g)–> 2NO(g)

b) very high temp

Question 14

write the equations which represent how nitrc oxide causes acid rain

Answer 14

equation 1)
2NO+ O2–> 2NO2

equation 2)
4NO2+ O2+2H20–> 4HNO3

Question 15

what is the equation between sulfur dioxide and calcium oxide

b) type of reaction?

Answer 15

SO2(g)+ CaO(s)–> CaSO3(s)

b) neutralisation and acid base

Question 16

What are the advantages of using a mesh coated with calcium oxide to remove
SO2 from waste gases?

Answer 16

• mesh leads to bigger SA for calcium oxides

-mesh leads to more frequent particle collisions

Question 17

outline process of fractional distillation

Answer 17

1) crude oil is heated in a furnace to make a vapour
2) column has a negative temperature gradient
3) fractions seperate by boiling point
4) larger molcules condense nearer the bottom of the column

Question 18

outline the name of the fractions from bottom to top

Answer 18

1) Bitumen
2) Fuel Oil
3) Lubricating oil
4)Diesel Oil
5) Kerosene
6) Petrol
7) Gas

Question 19

What is Bitumen used for

Answer 19

roofing+ tarmac

Question 20

what is fuel oil used for

Answer 20

ships

Question 21

what is Diesel Oil used for

Answer 21

diesel fuel

Question 22

what is kerosene used for

Answer 22

jet fuel + heating

Question 23

what is petrol used for

Answer 23

petrol cars

Question 24

what is gases used for

Answer 24

gas stove

Question 25

define cracking

Answer 25

conversion of large hydrocarbons to smaller hydrocarbon molecules by breakage of C-C bonds

Question 26

what is the economic reasons for cracking

Answer 26

The petroleum fractions with shorter C chains are in more demand than larger fractions. The products of cracking are more valuable than the starting materials (e.g. ethene used to make poly(ethene), branched alkanes for motor fuels, etc.)

Question 27

conditions needed for thermal cracking

Answer 27

High temperature ( 1000 °C) High pressure ( 70 atm/ 7000kPa)

Question 28

what are the products of thermal cracking

Answer 28

produces mostly alkenes

Question 29

conditions needed for catalytic cracking

Answer 29

-High temp (450°C) -Slight pressure -zeolite catalysts used which helps lower the temperature needed.

Question 30

products of catalytic cracking

Answer 30

Produces branched and cyclic alkanes and aromatic hydrocarbons for motor fuels

Question 31

Explain how CO and NO are removed from the exhaust gases and why the removal of each of them is desirable

Answer 31

1)Catalytic converter 2) uses Pt / Rh / Pd / Ir 3)reduces EA 4)2NO + 2CO → N2 + 2CO2

Question 32

Identify a catalyst used in a catalytic converter

Answer 32

Platinum or palladium or rhodium

Question 33

Write an equation to show how nitrogen monoxide is removed from the exhaust gases as they pass through a catalytic converter.

Answer 33

2NO + 2CO → N2 + 2CO2

Question 34

Outline the essential features of the fractional distillation of crude oil that enable the crude oil to be separated into fractions.(4)

Answer 34

Fractions or hydrocarbons or compounds have different boiling points bp depends on size Temp gradient in column heavier molecules at bottom

Question 35

Write an equation to show how one molecule of C14H30 is cracked to form one molecule of C8H18 and one molecule of another hydrocarbon. Explain why oil companies need to crack ‘suitable heavy fractions (4)

Answer 35

Large molecules or compounds or long chain hydrocarbons (broken) into smaller molecules or compounds or smaller chain hydrocarbons; Zeolite or aluminosilicate (catalyst); C14H30 → C8H18 + C6H12; Smaller chain molecules are in more demand or have higher value or vice versa;

Question 36

Write an equation for the incomplete combustion of C8H18 to form carbon monoxide and water only. A catalytic converter is used to remove carbon monoxide from the exhaust gases in a car. Identify a catalyst used in the catalytic converter. Write an equation to show how carbon monoxide is removed in a catalytic converter. State why the water produced in the exhaust gases may contribute to global warming.

Answer 36

C8H18 + 8½ O2 → 8CO + 9H2O; Rh/ Pd/Pt/lr 2CO + 2NO → 2CO2 + N2 / 2CO + O2 → 2CO2; Greenhouse gas