3.2 - Alkanes Flashcards

1
Q

What are the 3 stages of the mechanism of Halogenation of Alkanes?

A

|> Initiation
|> Propagation
|> Termination

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2
Q

Name of mechanism: Halogenation of Alkanes

A

Free-radical Substitution

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3
Q

Define: Propagation (free-radicals)

A

Formation of Free Radicals

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4
Q

What is produced from catalytic cracking?

A

|> Cyclic & branched Alkanes

|> Aromatic Rings (e.g. Benzene)

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5
Q

Define: Initiation (free-radicals)

A

Formation of radicals under UV light

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6
Q

What does Thermal Cracking produce?

A

|> Alkanes

|> High % of Alkenes

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7
Q

What are the Catalysts used in Catalytic Converters?

A

Rh, Pd, Pt

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8
Q

As the length of a carbon chain increases, the boiling point ____ ?

A

Increases

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9
Q

Why are power station chimneys coated with CaO or CaCO₃?

A

Remove Sulfur Dioxide from Flue Gas

Form Plasterboard

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10
Q

What are the Conditions for Halogenation of Alkanes?

A

U.V. Light

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11
Q

Why does boiling point decrease as no. of branches increases?

A

|> Less points of contact
|> VDWs become weaker
|> Less energy to break

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12
Q

What conditions is Thermal Cracking carried out at?

A

v. High Temp

High Pressure

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13
Q

Why are Alkanes not soluble in Water?

A

|> They are non-polar

|> Water molecules are held together by hydrogen bonds, which are much stronger than VDWs

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14
Q

What is produced from Further Incomplete combustion of Alkanes?

A

solid C & H₂O

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15
Q

Define: Structural isomers

A

Molecules with the same molecular formula but a different structural formula

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16
Q

What are the products of Catalytic Cracking used for?

A

Motor Fuels

17
Q

Why does boiling point Increase as Chain Length Increases?

A

|>More electrons
|>Stronger temporary dipoles
|>More energy needed to break

18
Q

Define: Saturated Hydrocarbons

A

Only contain single C-C bonds

19
Q

Define: Cycloalkane

A

|> Have general formula CnH₂n

|> Named according to largest ring

20
Q

What Inter-molecular forces attract neighbouring Alkane molecules?

A

weak VDWs

21
Q

As the number of Branches in an Alkane Increases, the boiling point ____ ?

A

Decreases

22
Q

What is produced from Incomplete combustion of Alkanes?

A

CO & H₂O

23
Q

Are alkanes polar or non-polar?

A

|> Non-polar

|> C & H have similar electronegativity vaues

24
Q

Define: Hydrocarbon

A

Compounds that contain Carbon & Hydrogen atoms only

25
Q

What is produced from Complete combustion of Alkanes?

A

CO₂ & H₂O

26
Q

Define: Free-radical

A

Species with an Unpaired electron

27
Q

What type of reaction is Halogenation?

A

Substitution

H atom replaced by Halogen atom

28
Q

Define: Chain isomers

A

Same molecular formula, different longest chain lengths with -yl groups

29
Q

Why are Alkanes non-polar?

A

C & H have very similar electronegativity values

30
Q

Shape and Bond Angle around a C atom?

A

Tetrahedral

109.5°

31
Q

What is the general formula for Aliphatic (chain) Alkanes?

A

CnH₂n₊₂

32
Q

Why do catalytic converters have a honeycomb structure?

A

Larger Surface Area

33
Q

What do Catalytic Converters remove?

A

CO, NOₓ & unburned hydrocarbons

34
Q

How is Catalytic Cracking carried out?

A

High Temperature
Slight Pressure
Zeolite (porous solid) Catalyst

35
Q

How are Nitrogen Oxides (NOₓ) produced?

A

N₂ + O₂ & electrical spark