6 Organic Chemistry Flashcards
Define “catenation”
The ability to form bonds between atoms of the same element
Types of formulae?
- molecular formula
- empirical formula
- structural formula
- displayed formula
- skeletal formula
Describe “nucleophile”
- has a lone pair to form a new bond
- attacks electron deficient areas
Describe “electrophile”
- has a + charge or δ+ charge
- attacks electron rich areas
Describe “free radical”
- has an unpaired electron that wants to pair up
- very reactive
- attacks everywhere
Types of reaction?
- addition
- substitution
- elimination
- polymerisation
- hydrolysis
What are the two bonds in a double bond?
- sigma (σ) bond formed by 2 sp2 orbitals overlapping
- pi (π) bond formed by 2 2p overlapping
Describe the combustion of alkenes
- high ΔHc
- smoky flame die to ratio of carbon to hydrogen (carbon particulates)
- rarely used
Conditions for addition of alkenes?
- at 150 degrees Celsius in the presence of nickel catalyst for hydrogen
- acid catalyst is used to add steam to produce alcohol
- addition of halogens and hydrogen halides can be carried at room temperature without catalyst
- potassium manganate (VII) is used in oxidation to produce diol with acid catalyst at room temperature
How can the presence of a double bond be tested?
Colour change during addition of halogens or oxidation
Describe “electrophilic addition”
- at room temperature
- no catalyst or UV light required when non-polar molecules act as reagents
Describe “Markownikoff’s rule”
- in the electrophilic addition to alkenes the major product is formed via the more stable carbocation
- the stability depends on the number of alkyl groups attached as they exert an inductive effect on the carbocation
Difference between aliphatic and aromatic alcohol?
- the OH replaces an H in a basic hydrocarbon skeleton in aliphatic alcohols
- the OH is attached to directly to the ring in aromatic alcohols
Structure of benzene?
- six π electrons are delocalised around the ring by overlapping the p orbitals
- no double bonds and all bond lengths are equal
- planar structure
Chemical properties of alcohols?
- bases
- nucleophiles (lone pair on oxygen)
- useful fuel (high ΔHc)
Reaction is alcohols with sodium?
- at room temperature
- sodium alkoxide and hydrogen is produced
- alkoxides are white crystalline solids
Chlorination of alcohols?
Reagent: phosphorus (V) chloride
Mechanism: substitution
Product: halogenoalkane
Notes: HCl seen as misty white fumes, works well for primary halogenoalkane production
Reagent: concentrated hydrochloric acid
Mechanism: substitution
Product: halogenoalkane
Notes: great for production tertiary halogenoalkanes
Bromination of alcohols?
Reagents: concentrated hydrobromic acid (HBr) or sodium/potassium bromide + 50% concentrated sulfuric acid
Conditions: reflux (heating to cause evaporation and condensation)
Products: halogenoalkane and water
Reagents: phosphorus (III) or (V) bromide
Product: halogenoalkane and phosphorus acid
Iodination of alcohols?
Reagents: phosphorus (III) iodide
Products: halogenoalkane and phosphorus acid
Conditions: red phosphorus and iodine mix in reaction flask to react with alcohol
