Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Organic Chemistry > 3.3.2 Alkanes > Flashcards

3.3.2 Alkanes Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

what is the general formula of an alkane?

A

CnH2n+2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the general formula of cycloalkanes?

A

CnH2n

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is an alkane?

A

saturated hydrocarbon containing C-H bonds only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Are alkanes’ bonds polar? why/why not?

A

non-polar - carbon and hydrogen have similar electronegativities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which intermolecular forces do alkanes have? Why?

A

Only Van der Waals forces of attraction - bonds are non-polar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Are alkanes soluble in water? Why?

A

No, hydrogen bonds in water are stronger than alkanes’ Van der Waals forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How reactive are alkanes?

A

Very unreactive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which reactions will alkanes undergo?

A

Combustion
Reaction with halogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is crude oil? How is it formed? Is it renewable? Why?

A

Mixture of fractions (hydrocarbons with similar boiling points and properties)
Formed at high temperatures and pressures deep below earth’s surface over millions of years
Non renewable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is fractional distillation? How does it work?

A

Crude oil heated until it is vaporised
Passed into a fractioning tower that is cooler at the top than the bottom
Vapours rise up the column and - via trays and bubble caps - condense when temperature is lower than their boiling point
Shorter chain alkanes condense at the top - they have the lowest boiling points

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why are alkanes cracked?

A

to turn a long chain alkane into shorter ones and an alkene.
Shorter chains are more useful

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the conditions for Thermal cracking?

A

700-1200K temp
Up to 7000kPa pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the intermediate for the thermal cracking reaction?

A

Free radicals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the main products of thermal cracking?

A

Alkenes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the conditions for catalytic cracking?

A

Lower temperature
Lower pressure
Zeolite catalyst with a honeycomb structured give a large SA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the main products of catalytic cracking?

A

Cycloalkanes, aromatic hydrocarbons, branched alkanes

16
Q

Write an equation for the combustion of propane.

A

C3H8 + 5O2 —> 3CO2 + 4H2O

17
Q

What is a fuel?

A

Something which releases heat energy when combusted

18
Q

What are the five main fuels comprising of alkanes?

A

Methane, butane, propane, petrol, paraffin

19
Q

What is incomplete combustion and what products are formed in the case of alkanes?

A

Combustion in a limited supply of oxygen
CO - carbon monoxide - poisonous
C - carbon particulates - soot - global dimming

20
Q

Which type of hydrocarbons are most likely to undergo incomplete combustion?

A

Longer chains

21
Q

What is the environmental impact of carbon monoxide?

A

Toxic / poisonous

22
Q

What is the environmental impact of nitrogen oxides?

A

Form nitric acid —> acid rain, smog

23
Q

What is the environmental impact of sulphur impurities/sulphur dioxide?

A

Form sulphuric acid —> acid rain

24
Q

What is the environmental impact of soot (carbon)?

A

Asthma, cancer, global dimming

25
Q

What is the environmental impact of unburnt hydrocarbons?

A

Smog

26
Q

What is the environmental impact of carbon dioxide?

A

Greenhouse gas —> global warming

27
Q

What is the environmental impact of water vapour?

A

Greenhouse gas —> global warming

28
Q

What are flue gases?

A

Gases given out by power stations

29
Q

What can we use to desulphurise flue gases?

A

CaO
CaCO3

30
Q

What are catalytic converters made up of?

A

Ceramic honeycomb coated with platinum, palladium and rhodium metals

31
Q

What are greenhouse gases?

A

Gases which trap infrared radiation, making earth like a greenhouse

32
Q

What is the greenhouse effect? How does it contribute to global warming?

A

Greenhouse gases trap infrared radiation in the atmosphere, atmosphere heats up

33
Q

Define carbon neutral activities?

A

Produce no net / overall carbon dioxide emissions

34
Q

How are halogenoalkanes formed from alkanes?

A

Free radical substitution reactions

35
Q

What are the three stages of free radical substitution?

A

Initiation - breaking halogen bond to form free radicals
Propagation - chain part of the reaction where products are formed but free radical remains
Termination - free radicals removed, stable products formed

36
Q

What are the conditions needed for the formation of a free radical chlorine atom?

A

Presence of UV light

37
Q

What is the ozone layer’s function?

A

Protects the earth from harmful exposure to too many UV rays

38
Q

How do CFCs break the ozone layer down?

A

Free radical substitution

Organic Chemistry (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions