Brainscape's Knowledge GenomeTM

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


See full index

CHEMISTRY > ALKANES > Flashcards

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

Define saturated

A

No double bond

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

Define hydrocarbon

A

Molecule containing only C and H

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

What two factors affect alkane boiling points

A

Carbon chain length, number of branches

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

Boiling point increases as chain length increases because:

A

•alkanes have induced dipole dipoles between molecules
•strength of bonds increases as size of molecule increases
•the longer the C chain, the bigger the molecule, the more e-

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

How do more branches affect boiling point?

A

•more branches decrease boiling point
•there is more surface contact between lower branched molecules
•the induced dipole dipole attractions between molecules of lower branched molecules are stronger

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

How does fractional distillation work?

A

Separates hydrocarbons based on their different boiling points

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

What is a fraction

A

A group of hydrocarbons with the same boiling point

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

What is the process of fractional distillation? (6m)

A

•crude oil is vapourised and enters column at the bottom
• the mixture of HC have different boiling points
•their boiling points depend on chain length and branching
•it is hotter at the bottom of the column
•larger molecules condense first at the bottom and collect

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

What is cracking?

A

Breaks larger fractions into smaller fractions

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

Why do we use cracking?

A

To produce more useful, shorter chain molecules that are higher in demand

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

What does thermal cracking use

A

High temperature and pressure

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

What temperature does thermal cracking use?

A

700-1200K

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

What pressure does thermal cracking use?

A

7000kPa

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

What are the products of thermal cracking?

A

One alkane, the rest alkenes

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

What temperature does catalytic cracking use?

A

720K

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What pressure does catalytic cracking use?

A

100kPa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What catalyst does catalytic cracking use?

A

Zeolite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is produced with catalytic cracking?

A

High percentage of branched alkanes and cycloalkanes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are cycloalkanes used for?

A

Motor fuels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is combustion?

A

Reaction with oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is needed for complete combustion

A

Excess oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the products of complete combustion?

A

CO2 and H2O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the reaction for complete combustion of methane

A

CH4 + 2O2 -> CO2 + H20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is methane used for?

A

Domestic heating and cooking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are products of incomplete combustion?

A

CO and H20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Why is CO harmful

A

Toxic as it prevents oxygen from binding to haemoglobin in blood cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are two harmful products of combustion

A

SO2 and NO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Equation for production of SO2

A

S(s) + O2 -> SO2

29
Q

Why is sulfur dioxide formed?

A

Sulfuric impurities appear in crude oil

30
Q

What does sulfur oxide and nitrogen oxide cause

A

Acid rain

31
Q

Why is acid rain harmful

A

Causes erosion of buildings and lake contamination

32
Q

What does sulfur dioxide do in rain water

A

Dissolve

33
Q

Give the equation of the reaction of SO2 with rain water

A

SO2 + 1/2 O2 + H2O -> H2SO4

34
Q

Why are nitrogen oxides formed after combustion?

A

Fuels burn in air which is 80% oxygen

35
Q

Give equation for the formation of nitrogen oxide

A

N2 + O2 -> 2NO

36
Q

Give equation for the formation of nitrogen dioxide

A

2NO + O2 -> 2NO2

37
Q

What is the equation with nitrogen that causes acid rain

A

4NO2 + 2H2O + O2 -> 4HNO3

38
Q

Why are unburnt hydrocarbons harmful

A

Toxic and cause cancer

39
Q

How do unburnt hydrocarbons arise

A

Escape into air before being used up

40
Q

What are the two ways to reduce pollution

A

Fluent gas desulphurisation and catalytic converter

41
Q

How does flue gas sulphurisation work

A

Neutralises acidic SO2 with alkali

42
Q

What does flue gas desulfurisation use

A

Calcium oxide and calcium carbonate

43
Q

What does the reaction with calcium oxide and SO2 produce

A

CaSO4.2H2O

44
Q

What is CaSO4.2H2O used for

A

Builders’ plaster

45
Q

What does calcium carbonate and SO2 produce

A

CaSO4

46
Q

How does a catalytic converter work?

A

Converts harmful gases into less harmful gases

47
Q

What is the structure of a catalytic converter?

A

Honeycomb

48
Q

Why does a catalytic converter have a honeycomb structure?

A

Increased surface area for a faster rate of reaction

49
Q

What metals is a catalytic converter made of

A

Platinum and rhodium (catalysts)

50
Q

What does NO and CO produce in a catalytic converter?

A

N2 and CO2

51
Q

What do unburnt hydrocarbons and NO produce in a catalytic converter

A

CO2 H2O N2

52
Q

Polluting effect of CO2

A

Greenhouse gas

53
Q

Polluting effect of H2O

A

Greenhouse gas

54
Q

Polluting effect of CO

A

Poisonous

55
Q

Polluting effect of solid Carbon

A

Damages lungs

56
Q

Three characteristics of the homologous series are:

A

•differ by CH2
•chemically similar
•show a trend in physical properties

57
Q

The order of fractions from lowest boiling point to highest

A

Mineral oil, gas oil (diesel), kerosene (paraffin), naphtha, petrol (gasoline)

58
Q

What does the term carbon-neutral mean?

A

An activity with no overall carbon emissions

59
Q

What is the use of a short chain alkane?

A

Fuel

60
Q

What is the use of a long chain alkane

A

Any of the high BP fractions eg. Fuel oil, kerosene, petrol

61
Q

Use of an alkene

A

Poly (alkene)

62
Q

How are nitrogen oxides formed in engines (2m)

A

•N2 reacts with oxygen IN AIR
•at high temperatures

63
Q

With which mechanism does chlorination occur?

A

Free-radical substitution

64
Q

What are the reagents and conditions of chlorination

A

Cl2 , UV light

65
Q

What are the steps in chlorination/free radical substitution?

A

•initiation
•propagation
•termination

66
Q

What is the equation of the initiation step of chlorination

A

UV light
Cl2 —-> 2Cl•

67
Q

What is the propagation step of chlorination of ethane?

A

Cl• + CH3CH3 –> •CH2CH3 + HCl
•CH2CH3 +Cl2 –> CH2ClCH3 + Cl•

68
Q

What is the termination step of chlorination?

A

Two radicals combine

CHEMISTRY (12 decks)

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