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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
What are 2 examples of homologous series?
Alkanes and alkenes
26
What is the formula for complete combustion?
ex: methane CH4 + 2 O2 -> CO2 + 2 H2O Combustion results in CO2 and water
27
What is the formula for incomplete combustion?
Enough oxygen -> complete combustion Not enough oxygen to burn -> incomplete combustion CH4 + O2 -> C + 2 H2O Results in CO and carbon particulates -> dangerous
28
What reaction to alkanes can be used to produce alkenes?
Cracking
29
What is cracking?
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
How is catalytic cracking done?
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
How does demand make catalytic cracking useful?
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
How can you recognize a alkane or alkene from: Molecular structure Reaction with aqueous bromine
Molecular structure: Double bond -> alkene Only single bonds -> alkane Reactions: Aqueous bromine -> yellow/orange color Lose color -> alkene Same color -> alkane
33
What happens when bromine reacts with an alkene?
Ex: Ethene C2H4 + Br2 -> C2H4Br2 Ethene + bromine -> dibromethane Structure: bromine added across double bond Hydrogen moved to sides
34
What happens when hydrogen reacts with an alkene?
Ex: ethene C2H4 +H2 -> C2H6 Ethene + hydrogen -> ethane Hydrogenation reaction -> done with a catalyst and high temps
35
What happens when an alkene reacts with steam?
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
How is ethanol formed via fermentation?
Glucose -> ethanol + carbon dioxide C6H1206 -> 2 C2H5OH + 2 CO2 Yeast -> fungus without air -> anaerobic respiration -> yeast metabolises sugar Ethanol removed via distillation
37
What is the product of complete combustion of ethanol?
C2H5OH + 3 O2 -> 2 CO2 + 3 H2O Ethanol burns blue
38
What is ethanol used as?
Solvent: Perfumes, cosmetics Printing inks and glues Fuel: Mixed with petroleum or fuel for cars -> less polluting Less reliance on petrol or diesel
39
What are polymers?
Long chain molecules formed by small units called monomers
40
What is (addition) polymerisation?
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
What does the structure of a monomer or polymer look like?
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
Describe the structure and name of a polymer that has 1 chlorine and another with 4 fluorine
Chloroethene -> one chlorine atoms in ethene structure-> becomes poly(chloroethene) Tetrafluoroethene -> hydrogen replaced by fluoride in ethene structure -> becomes poly(tetrafluoroethene)
43
How can you convert repeat unit <=> monomer?
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
What is condensation polymerisation?
2 monomers linked by the removal of a small molecule, usually water
45
What is the difference between between addition and condensation polymerisation?
Addition: Forms only polymer molecules Condensation: Forms polymer molecules and one H2O molecule
46
How is nylon formed (condensation polymerisation)?
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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