Organic chem Flashcards
What is petroleum made of
Mixture of hydrocarbons, mainly alkanes
How does fractional distillation work
Low bp at top, High bp at bottom
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Refinery gas, Petrol, Naphtha, Kerosine, Diesel, Lubricating Oil, Fuel Oil, Bitumen
Properties of Carbon
- Tetravalent
- Can bond to each other to form long chain like structures
- C-C bonds are very strong, leading to greater stability for compounds that contain it
Number of carbon atoms
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Meth
Eth
Prop
But
Pent
Hex
Hept
Oct
Non
Dec
Prefixes
Methyl
Ethyl
Propyl
Butyl
Functional group of carboxyl acids are always where?
On first carbon atom (so no need to state in naming)
What are isomers
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
Types of isomers
Structural, Positional, Functional
When naming halogenoalkanes with substituents, write the halogen first
eg. 1-bromo 2-methylbutane
How to name the halogens
Bromo Fluoro Chloro
Types of organic reactions
- Addition
- 2 reactants become 1 product - Elimination
- 1 reactant + base –> 2 products
- number of products > number of reactants
(eg. 1-bromobutane take out the bromine and replace with H) - Substitution
- 2 reactants exchange parts to form two new products
Complete vs Incomplete combustion
Complete will produce CO2 but incomplete (limiting reactant is O2) produces CO
Saturated vs unsaturated
Saturated is C-C bonds
Unsaturated is C=C double bonds
Alkanes general formula
Cn H2n+2
Solubility of alkanes
Insoluble in water, Soluble in organic solvents
How many alkanes are gases
First 4
First few alkenes also gases
Alkanes boiling/melting point trend
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 vs Straight-chain alkanes
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
Alkanes viscosity
Increases as carbon increases
Greater molecular size, flows less easily
Flammability of alkanes
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
Density of alkanes
Increases as carbon atoms increase
Chemical property of alkanes
Generally unreactive because the C-C and C-H bonds are strong and hard to break
Combustion of alkanes
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
Cracking of alkanes (product + conditions)
Produces alkenes (ALWAYS)
Conditions:
600˚C + SiO2 or Al2O3 catalyst