3.3.2 - Alkanes

Question 1

General formula for straight/branched chain alkanes?

Answer 1

CnH2n+2

Question 2

General formula for cyclic alkanes?

Answer 2

CnH2n

Question 3

What is the bond angle in straight chain alkanes?

Answer 3

109.5 degrees

Question 4

Are alkanes polar?

Answer 4

No

Question 5

Are alkanes soluble?

Answer 5

No

Question 6

What IMFs are between alkane molecules?

Answer 6

vdWs’ only

Question 7

How do you get from an alkane to a haloalkane?

Answer 7

Free radical substitution

Question 8

What carbon chain length in gaseous alkanes?

Answer 8

1-4

Question 9

What carbon chain length in liquid alkanes?

Answer 9

5-17

Question 10

What carbon chain length in solid alkanes?

Answer 10

18+

Question 11

Solid alkanes have a ______ feel to them

Answer 11

Waxy feel

Question 12

What is fractional distillation?

Answer 12

Separating crude oil into different fractions based on boiling point

Question 13

What is a fraction?

Answer 13

Hydrocarbon molecules of similar carbon chain lengths and properties

Question 14

Fractional distillation is a ______ process - why?

Answer 14

Physical process: vdW forces between alkane molecules are overcome in vaporisation and reformed in condensation

Question 15

Unburnt hydrocarbons can form what? Why is this bad?

Answer 15

Photochemical smog - carcinogenic

Question 16

Temp of top and bottom of fractionating tower/column?

Answer 16

Top - 400K

Bottom - 630K

Question 17

What is ‘cracking’?

Answer 17

Breaking C-C bonds in alkanes to produce a mixture of shorter chain alkanes and alkenes that are more economically valuable

Question 18

Two types of cracking?

Answer 18

Thermal and catalytic

Question 19

Describe thermal and catalytic cracking

Answer 19

Thermal: 1000degrees C; 70atm; no catalyst
Catalytic: 450degrees C; slight Pa; honeycomb zeolite catalyst

Question 20

Main products of thermal and catalytic cracking

Answer 20

Thermal: alkenes
Catalytic: cycloalkanes; aromatic compounds; motor fuels; branched alkanes

Question 21

What are catalytic converters made from?

Answer 21

Platinum and rhodium in a honeycomb structure

Question 22

What is the aim of flue gas desulfurisation?

Answer 22

To remove SO2 from the combustion of coal

Question 23

Use of very short chain alkanes?

Answer 23

Camping gas (butane, propane)

Question 24

Use of gasoline?

Answer 24

Car petrol

Question 25

Use of naptha?

Answer 25

Photochemical production

Question 26

Use of kerosene?

Answer 26

Jet fuel

Question 27

Use of diesel oil?

Answer 27

Lorry fuel

Question 28

Use of lubricating oil?

Answer 28

Candles/engine oil

Question 29

Use of fuel oil?

Answer 29

Ships/power station fuel

Question 30

Use of tar/bitumen?

Answer 30

Roads/roofing