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Y4 Chem > Organic chem > Flashcards

Organic chem Flashcards

1
Q

What is petroleum made of

A

Mixture of hydrocarbons, mainly alkanes

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2
Q

How does fractional distillation work

A

Low bp at top, High bp at bottom
Real Ppl Never Kill Dear by Large (Firing) Bullets

Refinery gas, Petrol, Naphtha, Kerosine, Diesel, Lubricating Oil, Fuel Oil, Bitumen

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3
Q

Properties of Carbon

A
  1. Tetravalent
  2. Can bond to each other to form long chain like structures
  3. C-C bonds are very strong, leading to greater stability for compounds that contain it
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4
Q

Number of carbon atoms

A

Mostly everyone passes but people have help on days

Meth
Eth
Prop
But
Pent
Hex
Hept
Oct
Non
Dec

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5
Q

Prefixes

A

Methyl
Ethyl
Propyl
Butyl

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6
Q

Functional group of carboxyl acids are always where?

A

On first carbon atom (so no need to state in naming)

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7
Q

What are isomers

A

2 or more compounds with the same molecular formula but exist in different forms due to a difference in arrangement of the atoms in the molecule

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8
Q

Types of isomers

A

Structural, Positional, Functional

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9
Q

When naming halogenoalkanes with substituents, write the halogen first

A

eg. 1-bromo 2-methylbutane

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10
Q

How to name the halogens

A

Bromo Fluoro Chloro

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11
Q

Types of organic reactions

A
  1. Addition
    - 2 reactants become 1 product
  2. Elimination
    - 1 reactant + base –> 2 products
    - number of products > number of reactants
    (eg. 1-bromobutane take out the bromine and replace with H)
  3. Substitution
    - 2 reactants exchange parts to form two new products
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12
Q

Complete vs Incomplete combustion

A

Complete will produce CO2 but incomplete (limiting reactant is O2) produces CO

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13
Q

Saturated vs unsaturated

A

Saturated is C-C bonds
Unsaturated is C=C double bonds

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14
Q

Alkanes general formula

A

Cn H2n+2

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15
Q

Solubility of alkanes

A

Insoluble in water, Soluble in organic solvents

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16
Q

How many alkanes are gases

A

First 4
First few alkenes also gases

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17
Q

Alkanes boiling/melting point trend

A

Alkanes are simple covalent molecules held tgt by weak intermolecular forces
As number of carbon atoms increase, molecular size increases and electron cloud size increase
A greater amount of energy is needed to overcome the strong intermolecular forces of attraction
Hence increasing bp/mp

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18
Q

Branched-chain alkanes vs Straight-chain alkanes

A

Branched-chain alkanes are more spherical in shape and have less surface area of contact with neighbouring molecules, leading to weaker intermolecular forces
Less energy is required to overcome these forces, hence mp/bp lower than straight-chain alkanes

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19
Q

Alkanes viscosity

A

Increases as carbon increases
Greater molecular size, flows less easily

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20
Q

Flammability of alkanes

A

As molecular size increases, bp increases so flammability decreases
As carbon atoms increase, percentage of carbon in alkanes increase, produce smokier and sootier flames due to incomplete combustion

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21
Q

Density of alkanes

A

Increases as carbon atoms increase

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22
Q

Chemical property of alkanes

A

Generally unreactive because the C-C and C-H bonds are strong and hard to break

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23
Q

Combustion of alkanes

A

HIGHLY EXOTHERMIC MAKING THEM GOOD FUELS

Forms CO2 and H2O (gas)

Incomplete combustion will form CO and carbon as soot + H2O (gas)

eq. CxHy + (x + y/4)O2 —> xCO2 + (y/2)H2O

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24
Q

Cracking of alkanes (product + conditions)

A

Produces alkenes (ALWAYS)

Conditions:
600˚C + SiO2 or Al2O3 catalyst

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25
Q

Substitution of alkanes (products + conditions)

A

Produces halogenoalkanes

Conditions: UV light and halogen

Can become multi substituted when there is excess halogen and limited alkane

26
Q

How to get alkanes

A

From petroleum or crude oil

used as a fuel for heating etc.

27
Q

Alkenes general formula

A

Cn H2n

28
Q

Alkenes mp/bp trends

A

Same as alkanes
Alkanes are simple covalent molecules held tgt by weak intermolecular forces
As number of carbon atoms increase, molecular size increases and electron cloud size increase
A greater amount of energy is needed to overcome the strong intermolecular forces of attraction
Hence increasing bp/mp

Branched-chain alkanes are more spherical in shape and have less surface area of contact with neighbouring molecules, leading to weaker intermolecular forces
Less energy is required to overcome these forces, hence mp/bp lower than straight-chain alkanes

29
Q

Combustion equation for all (it hink)

A

CxHy + (x+y/4) O2 –> xCO2 + (y/2)H2O

30
Q

Alkenes vs alkanes flame/soot

A

Alkenes are sootier because higher % of carbon (double bonds means less hydrogen so % is higher)

31
Q

Alkane reactions

A

Combustion
Cracking
Substitution

32
Q

Alkene reactions

A

Combustion
Addition reactions
1. Hydrogenation
2. Bromination
3. Hydration
4. Addition polymerisation

33
Q

Explain the vegetable oil and margarine thing

A

Hydrogenation of vegetable oil increases its mp/bp so its still kind of solid at room temp (margarine)

Vegetable oil is the alkene and margarine is the alkane

34
Q

Bromination of alkenes

A

Add halogen to the original C=C double bond

At room temp and pressure

Need liquid bromine or bromine in tetrachloromethan (CCl4)

Alkene will decolourise the reddish brown bromine in CCl4 rapidly

35
Q

Hydration of alkene (product + conditions)

A

Addition of steam

Produces alcohol

Phosphoric (V) acid catalyst, 300˚C and 60 atm

36
Q

Alkanes vs Alkenes (reactivity, bromination, polymerisation, flame, sub/add reactions)

A

Alkanes
- generally unreactive
- does not react with bromine under normal conditions (need UVlight)
- does not have addition polymerisation
- less sooty flame
- substitution reactions

Alkenes
- very reactive
- bromination occurs (rapidly decolourises reddish brown bromine)
- addition polymerisation
- sootier flame
- addition reactions

37
Q

Test for alkene vs alkane

A

Add a few drops of liquid bromine at room temperature in the absence of UV light
Alkene will rapidly decolourise the reddish-brown liquid bromine

For gases, can bubble it into liquid bromine

38
Q

Hydrogenation of alkenes (products and conditions)

A

Produces alkanes

Add hydrogen gas

200˚C and nickel catalyst

39
Q

Alcohols formula

A

Cn H2n+1 OH

OH does not dissociate in water because it is covalently bonded to the C atom

40
Q

Alcohol vs alkane combustion

A

Alcohols produce less energy per unit mass (less efficient) (less exo than w alkanes)

41
Q

Alcohol oxidation

A

Forms carboxylic acid

Need acidified potassium manganate VII (as oxidising agent) and heat under reflux

Add oxygen and remove 2 hydrogen

since its oxidation, KMnO4 will go from purple to colourless

42
Q

Alcohols state

A

Liquids at room temp

43
Q

Alcohols solubility

A

Soluble in water

Decreases down the homologous series

Hydroxyl group can form hydrogen bonds with water molecules

44
Q

Alcohols bp + comparison to alkanes alkenes

A

Increases as carbon increases as molecular size increases, strength of intermolecular forces increase too

Have both van der Waals forces and hydrogen bonds which is stronger than just van der Waals forces in alkanes/alkenes hence higher bp/mp

45
Q

How to produce ethanol

A

Hydration of ethene

or

Fermentation of glucose w yeast (produces ethanol and co2)
- C6H12O6 –> 2C2H5OH + 2CO2
- the absence of O2 (if not will become ethanoic acid and water)

46
Q

Carboxylic acid formula

A

Cn H2n+1 COOH

47
Q

Carboxylic acid solubility +compare w alcohols

A

Very soluble as OH can form hydrogen bonds w water

More soluble than alcohols because COOH is more polar than OH and can form stronger hydrogen bonds

48
Q

Carboxylic acid mp/bp + compare w alcohol

A

Same explanation as alcohol

carboxylic acid has stronger hydrogen bonds between molecules than alcohol (hence greater bp/mp than alcohol)

49
Q

Electrical conductivity of carboxylic acids

A

can dissolve in water to produce mobile ions

50
Q

Carboxylic acids reaction w metals, bases, carbonates

A

same as acid-base etc reactions

51
Q

Solubility of esters

A

Insoluble

52
Q

What are esters used for

A

Sweet smelling colourless liquids
used for perfumes, food flavourings, solvents

53
Q

How to form esters

A

Reaction between alcohol and carboxylic acid to form ester + water

strong heat and strong concentrated base

54
Q

Roles of conc sulfuric acid in forming esters

A

Acts as a catalyst that speeds up the reaction

It is a drying agent and removes H2O as it is formed, causing the equilibrium (drive equil position to the right) to favour the forward reaction to increase yield

55
Q

what is a polymer

A

a long chain macromolecule that is bonded tgt by many small repeat units

56
Q

Types of polymers

A

Addition (alkenes)
- eg. Poly(ethene)

Condensation
- polyamides
- polyesters

57
Q

Addition polymerisation definition + conditions

A

successive linking tgt of unsaturated monomers without losing any molecules or atoms to form an addition polymer

High temp, high pressure, catalyst (to break C=C double bond)

58
Q

Repeat units have how many inside

A

ONLY 2

59
Q

Monomers of polyamides + linkage name

A

Dicarboxylic acid + diamine (NHH one)

forms amide linkage

eg. nylon

60
Q

Uses of polyamides and polyesters

A

polyamides: fabrics and garments

polyesters: make audio and video tapes and soft plastic bottles + fabrics

61
Q

Monomers of polyesters

A

Dicarboxylic acid + diol (alcohol)

forms ester linkage

eg. Terylene

Y4 Chem (10 decks)

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