Organic Chemistry Flashcards
What are organic compounds?
Molecules containing carbon, usually bonded to hydrogen, oxygen, or nitrogen, apart from oxides of carbon (e.g., CO₂) and carbonates.
What is a hydrocarbon?
Compounds made up of carbon and hydrogen only.
What type of bonds are involved in organic compounds?
All organic compounds involve covalent bonding between atoms.
What types of bonds can carbon form?
Single bonds (C–C, as in alkanes), double bonds (C=C, as in alkenes), and triple bonds (rare, in alkynes).
What is a homologous series?
A family of hydrocarbons with similar chemical properties who share the same general formula
What is the general formula for alkanes?
CₙH₂ₙ₊₂
What is the functional group for alkenes?
C=C (double bond)
What is the general formula for alcohols?
CₙH₂ₙ₊₁OH
What is the functional group for carboxylic acids?
–COOH
What are the properties of alkanes?
Saturated hydrocarbons that contain only single covalent bonds, are relatively unreactive, but undergo combustion and substitution reactions.
What is complete combustion of alkanes?
Alkane + O₂ → CO₂ + H₂O
What is an example of complete combustion?
CH₄ + 2O₂ → CO₂ + 2H₂O
What is incomplete combustion of alkanes?
Alkane + O₂ → CO + H₂O
Carbon monoxide (CO) is toxic.
What are substitution reactions in alkanes?
Involves replacement of a hydrogen atom by another atom (e.g., halogen) and requires UV light.
What is an example of a substitution reaction?
CH₄ + Cl₂ → UV CH₃Cl + HCl
What are the properties of alkenes?
Contain at least one carbon-carbon double bond (C=C) and are more reactive than alkanes due to the double bond.
What are addition reactions in alkenes?
Reactions where alkenes react with other substances, such as hydrogenation and hydration.
What is crude oil?
A mixture of hydrocarbons separated into fractions using fractional distillation.
What are the fractions obtained from crude oil in order of increasing boiling point?
Refinery gases, gasoline, kerosene, diesel, fuel oil, bitumen.
How does fractional distillation work for longer hydrocarbons
Longer hydrocarbons have higher boiling points so evaporate and condense near the bottom of the column.
Properties of long hydrocarbons
high boiling point, high viscocity (fluidness), dark colour and low flammability
How does fractional distillation work for shorter hydrocarbons
Shorter hydrocarbons have lower boiling points so evaporate first and condense higher up the column.
What is cracking?
The process of breaking down long-chain hydrocarbons into shorter, more useful ones (alkanes and alkenes).
What conditions are required for cracking?
Requires heat (600–700°C) and a catalyst (silica or alumina).
What is an example reaction of cracking?
C₁₀H₂₂ → C₈H₁₈ + C₂H₄
What is polymerization?
The process of joining many small molecules (monomers) to form a long chain (polymer).
What is addition polymerization?
A type of polymerization where monomers are alkenes.
What is an example of addition polymerization?
nC₂H₄ → [−CH₂−CH₂−]ₙ
What are common polymers?
Polyethene (from ethene, used in plastics) and polypropene (from propene, used in containers).
How is bromine water used in organic chemistry?
Tests for C=C bond, turning orange to colorless .
What is needed for an Alkane to react with bromine?
UV light (e.g sunlight)
Why is cracking is necessary, in terms of the balance between supply and demand for different fractions
Less short-chain hydrocarbons are produced than needed (e.g gasoline fraction) as there is a higher demand for short-chain hydrocarbons to be used as polymers for plastic, gasoline, and petrol for cars
