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Chemistry Igcse > C14 > Flashcards

C14 Flashcards

1
Q

How does the prefix of a alkane/alkene/etc. Related to the number of carbon atoms?

A

Meth -> 1
Eth -> 2
Prop -> 3
But -> 4
After that Normal Greek prefixes

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2
Q

What are the formula and structures of:
Methane
Ethane
Ethene
Ethanol

A

Methane -> CH4
Ethane -> C2H6
Ethene -> C2H4
Ethanol -> C2H5OH

Structure -> check notes

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3
Q

What is a hydrocarbon?

A

A compound made of only hydrogen and carbon atoms

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4
Q

What is an alkane?

A

A saturated (only single carbon-carbon bonds) hydrocarbon

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5
Q

What is the formula for an alkane?

A

CnH2n+2

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6
Q

What are the characteristics of alkanes?

A

Generally unreactive
Do undergo combustion
Can be cracked -> catalytic cracking

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7
Q

What are isomers?

A

Alkanes that have the same formula, but a different arrangement

Naming isomers:
Find longest line (ex: propane)
Then nest line (ex: methane)
Find which carbon atom the second line connects to the first line -> REMEMBER: it can be MIRRORED (ex: 2)
2 methyl propane

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8
Q

What are alkenes?

A

Unsaturated (at least 1 carbon-carbon double bond) hydrocarbon

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9
Q

What is the formula for alkenes?

A

CnH2n

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10
Q

Why is there no such thing as methene?

A

Because you need at least 2 carbon atoms to form a carbon carbon double bond

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11
Q

Why are alkenes more reactive that alkanes?

A

The double bond can open to create more bonds, making it more reactive that alkenes

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12
Q

How are alkenes named?

A

By number of carbon atoms (prefix) and ending in -ene (suffix)

The funky ones:
Ex: but-1-ene
1 shows which bond between carbon atoms is the double bond -> REMEMBER: it can be MIRRORED

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13
Q

What are alcohols?

A

Hydrogen and carbon with one -OH group

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14
Q

What is the formula for alcohols?

A

CnH(2n+1)OH

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15
Q

How are alcohols named?

A

Prefix: number of carbon atoms
Suffix: -anol

Funkies:
Ex: propan-1-ol
Shows where the -OH group is -> REMEMBER: it can be MIRRORED

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16
Q

Draw the structure of alkanes and alkenes, up to 4 carbon atoms

A

Do it and check

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17
Q

What are coal, natural gas and petroleum/crude oil?

A

They are all fossil fuels

All contain carbon -> when burned -> carbon + oxygen -> combustion -> CO2

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18
Q

What is the main component of natural gases?

A

Methane

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19
Q

What is petroleum?

A

A mixture of hydrocarbons

20
Q

Explain the separation of hydrocarbons in petroleum

A

Fractional distillation -> separated it into fractions (groups with similar chain lengths)

Molecules in each fraction -> similar boiling ponts

Fractional column: hot bottom and cool top -> each fraction condense at different temp/height -> smaller chain: top, bigger chain: bottom

21
Q

What are properties of the molecules within a fraction?

A

Viscosity:
Attraction between molecules high -> more viscous
Longer-> more attraction -> more viscous

Color:
Longer-> darker color

Melt/boiling points:
Longer -> more attraction -> more energy required to separate -> high boiling/melting point

Volatility:
Tendency of a substance to vaporise
Longer -> more attraction less voliatile

22
Q

What are the different fractions of petroleum?

A

In order from lowest -> highest boiling points

Refinery gas
Gasoline/petrol
Naphtha
Kerosene/paraffin
Diesel
Lubricant
Heavy fuel oil
Bitumen/paraffin wax

23
Q

What are the uses of each fraction?

A

85% -> fuel for heating and transport
8%-> plastics and chemicals

Refinery gas:
Bottled gas for heating/cooking

Gasoline/petrol:
Fuel for cars

Naphtha:
Feedstock for chemicals and solvent

Kerosene/paraffin:
Jet fuel

Diesel:
Diesel engine/gas oil

Lubricant:
Used in products with moving parts

Heavy fuel oil:
Ships and power stations

Bitumen/paraffin wax:
Surfacing roads, waterproofing roofs, wax -> candles and waterproofing

24
Q

What are properties of homologous series?

A

Compounds with:
Similar features + chemical properties
Same general formulas
Same functional groups

25
Q

What are 2 examples of homologous series?

A

Alkanes and alkenes

26
Q

What is the formula for complete combustion?

A

ex: methane

CH4 + 2 O2 -> CO2 + 2 H2O

Combustion results in CO2 and water

27
Q

What is the formula for incomplete combustion?

A

Enough oxygen -> complete combustion
Not enough oxygen to burn -> incomplete combustion

CH4 + O2 -> C + 2 H2O

Results in CO and carbon particulates -> dangerous

28
Q

What reaction to alkanes can be used to produce alkenes?

A

Cracking

29
Q

What is cracking?

A

The process of converting long chain molecules (usually alkanes) into short chain molecules

Done because short chain molecules are more useful

Can create: shorter alkanes, alkenes, hydrogen

30
Q

How is catalytic cracking done?

A

Heat to around 600-700°C -> compound vaporizes
Vapor passes over catalyst (Al3O2)
Breaks covalent bonds as the compound and catalyst come into contact -> thermal decompositions

31
Q

How does demand make catalytic cracking useful?

A

Short chain molecules are more in demand, and by converting less in demand long chain molecules into shorter ones, we create a bigger supply of short chain molecules

32
Q

How can you recognize a alkane or alkene from:
Molecular structure
Reaction with aqueous bromine

A

Molecular structure:
Double bond -> alkene
Only single bonds -> alkane

Reactions:
Aqueous bromine -> yellow/orange color
Lose color -> alkene
Same color -> alkane

33
Q

What happens when bromine reacts with an alkene?

A

Ex: Ethene

C2H4 + Br2 -> C2H4Br2
Ethene + bromine -> dibromethane

Structure: bromine added across double bond
Hydrogen moved to sides

34
Q

What happens when hydrogen reacts with an alkene?

A

Ex: ethene

C2H4 +H2 -> C2H6
Ethene + hydrogen -> ethane

Hydrogenation reaction -> done with a catalyst and high temps

35
Q

What happens when an alkene reacts with steam?

A

Ex: ethene

C2H4 + H2O -> C2H5OH
Ethene + steam -> ethanol
SO:
Alkene + steam -> alcohol

Usually uses a catalyst (phosphoric acid) and high temp+pressure -> double bond broken and water joins

36
Q

How is ethanol formed via fermentation?

A

Glucose -> ethanol + carbon dioxide
C6H1206 -> 2 C2H5OH + 2 CO2

Yeast -> fungus
without air -> anaerobic respiration -> yeast metabolises sugar

Ethanol removed via distillation

37
Q

What is the product of complete combustion of ethanol?

A

C2H5OH + 3 O2 -> 2 CO2 + 3 H2O

Ethanol burns blue

38
Q

What is ethanol used as?

A

Solvent:
Perfumes, cosmetics
Printing inks and glues

Fuel:
Mixed with petroleum or fuel for cars -> less polluting
Less reliance on petrol or diesel

39
Q

What are polymers?

A

Long chain molecules formed by small units called monomers

40
Q

What is (addition) polymerisation?

A

Monomers join to make polymers (monomer must have a double bond -> alkene) (polymer only has single bonds -> will join other building blocks )
Usually involves increased temp+pressure and a catalyst

Addition -> means it is an addition reaction -> double bond breaks and forms a bond with any adjacent monomer

41
Q

What does the structure of a monomer or polymer look like?

A

Base:
Ex: ethene
Monomer: ethene -> has double bond
Polymer: poly(ethene) -> no double bonds, brackets, lines always go out of brackets (suggest it will connect to others of the same), n subscript -> number of building blocks

42
Q

Describe the structure and name of a polymer that has 1 chlorine and another with 4 fluorine

A

Chloroethene -> one chlorine atoms in ethene structure-> becomes poly(chloroethene)

Tetrafluoroethene -> hydrogen replaced by fluoride in ethene structure -> becomes poly(tetrafluoroethene)

43
Q

How can you convert repeat unit <=> monomer?

A

Monomer -> repeat unit:
Double bond -> single bond
Add bonds to achieve end (out of parentheses
Subscript on bottom right with number of units

Repeat unit -> monomer:
Single bond -> double bond
Remove side bonds
Subscript goes in front of monomer

44
Q

What is condensation polymerisation?

A

2 monomers linked by the removal of a small molecule, usually water

45
Q

What is the difference between between addition and condensation polymerisation?

A

Addition:
Forms only polymer molecules

Condensation:
Forms polymer molecules and one H2O molecule

46
Q

How is nylon formed (condensation polymerisation)?

A

LOOK AT NOTES FOR A DIAGRAM

Nylon -> made from HOOCC2H4COOH (carboxylic acid) and H2NC2H4NH2 (diamine)
NOTE: notice how in the acid there are -COOH groups at both ends (mirror) and that same for the diamine with -NH2 groups (mirror)

OH (from acid) and H (from diamine) -> H2O (condensation polymerisation)
-> link created where they were -> nylon unit formed

When drawn -> unit mirror back and forth -> possible because the ends of the initial acid and diamine are mirrored
Filled in box -> carbon chain
Not filled box -> nitrogen chain
MAKE SURE THERE ARE ONLY N-N AND C-C BONDS AT THE ENDS OF THE UNITS

Chemistry Igcse (10 decks)

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