organic chem Flashcards
(57 cards)
Organic compounds (definition)
Compounds whose molecules contain a significant amount of carbon
Hydrocarbons
Compounds which contain only H and C
Fractional distillation
Peter Pan Never Kiss Donkey’s Little Fluffy Butt (Petroleum gas, Petrol, Naphtha, Kerosene, Diesel, Lubricating oil, Fuel oil, Bitumen)
[Heater at bottom]
Volatility increase upwards
Flow/ignite more easily upwards
Properties of carbon (2)
- Each contains 4 valence electrons (tetravalent)
- Can form strong bonds with each other to form long chain-like structures, stable
Prefix
- Methyl (CH3)
- Ethyl (CH2CH3)
- Propyl (CH2CH2CH3)
- Butyl (CH2CH2CH2CH3)
*increases by one CH2
*add di-/tri- etc if got more than one substituent
Parent
- Meth-
- Eth-
- Prop-
- But-
Suffix
*highest priority: suffix, others: prefix
- Alkanes: -ane
- Alkyl (alkane with one hydrogen removed): alkyl-
- Alkenes: -ene
- Carboxylic acids: carboxy-/-oic acid
- Alcohols: hydroxy-/-ol
Isomerism types (4) + definition
Phenomenon in which ≥2 compounds with the same molecular formula exist in different forms due to different arrangement of atoms in the molecule
Structural (atoms in diff order)
Skeletal (diff carbon skeletons)
Positional (diff position of func groups)
Functional (diff func groups)
Addition
2 reactants –> 1 product
Elimination
1 reactant –> 2 products
Substitution
2 reactants –> 2 products (exchange parts)
Alkanes (general formula, functional group, name)
C n H 2n+2
NIL
-ane
Physical properties (alkanes)
- State: gas at room temp (first 4)
- Solubility: soluble in organic solvents, insoluble in water
- Low mp/bp
- Low density
Trends in physical properties (alkanes, alkenes, alcohols)
- mp/bp increase
- molecular size increase, electron cloud size increase
- larger amount of energy needed to overcome the stronger intermolecular FOA between atoms - viscosity/density increase
- molecular size increase, stronger intermolecular FOA between atoms
- molecules slide over each other less easily, more viscous and flow less easily - flammability decrease
- number of carbon atoms increase, boiling points increase, less flammable
- % of carbon in alkane molecules increase, flame produced more smoky/sooty
Effect of branching on mp/bp (alkanes/alkenes/alcohols/carboxylic acids)
Branched chain lower
- Branched chain more spherical in shape than straight chain
- Less SA of contact between neighbouring molecules
- Less energy needed to overcome intermolecular forces of attraction
Chemical properties (alkanes)
Generally unreactive, inert
Combustion of alkanes
Equation: CxHy (g) + O2 (g) –> H2O (g) + CO2 (g)
- Highly exothermic
- Complete produces water and CO2, - Incomplete produces soot (C) and carbon monoxide
Cracking of alkanes (definition, conditions, product, importance in oil industry)
Breaking down of long-chain hydrocarbons to form smaller, more volatile molecules
Conditions: 600ºC, SiO2/Al2O3 catalyst
Products: alkene + alkane/H2
Oil industry: greater supply/yield of fuels in demand
Cracking of paraffin (set-up)
Things to note:
a. Tilted boiling tube
b. Porcelain chips
c. Flame
d. Gas collection
Set-up
- Boiling tube: base is mineral wool soaked in liquid paraffin, middle is porcelain chips (directly over flame)
- Connected to beaker via delivery tube
- Delivery tube connected to inverted test tube (show production of gas)
Things to note
1. Tilted boiling tube: prevent paraffin and porcelain chips from reacting
2. Porcelain chips: catalyst, inc SA
3. Flame: needs high temperature
4. Gas collection: displacement of water (NOT gas syringe because hot air will expand it even without reaction)
Substitution of alkanes (reagents, conditions, products)
Reagents: alkane + halogens
Conditions: UV light
Products: halogenoalkanes + HX
Uses + sources of alkanes
Uses: fuel/paraffin wax/road surfacing
Sources: fractional distillation of crude oil
Alkenes (general formula, functional group, name)
CnH2n
C = C
-ene
Physical properties (alkenes)
Same as alkanes
Sources of alkenes
Cracking of alkanes