3A3 Organic Functional Groups and Compounds Flashcards
Recognize common organic functional groups, including alkanes, alcohols, ketones, and amines.
Define:
organic molecules
Molecules containing carbon and hydrogen.
Example: Methane (CH₄), the simplest organic compound.
Organic molecules can also contain oxygen, nitrogen, or other elements.
What is the basic building block of organic compounds?
Hydrocarbon, or a carbon bound to a hydrogen.
Hydrocarbons form the foundation of more complex organic molecules.
How is the base name of an organic compound determined?
Based on the number of carbon atoms in the longest chain.
For example, ‘prop’ for 3 carbons and ‘hex’ for 6 carbons.
True or False:
Inorganic molecules lack carbon.
False
Some inorganic compounds, like CO₂, contain carbon.
Define:
hydrocarbons
Compounds consisting of carbon atoms bonded only to hydrogen atoms.
Hydrocarbons form the backbone of organic compounds.
How are hydrocarbons classified?
Into four categories:
- Alkanes
- Alkenes
- Alkynes
- Arenes
Each category has distinct structural and chemical properties.
Alkanes contain single bonds, alkenes double bonds, alkynes triple bonds, and arenes an aromatic ring.
What are aromatic hydrocarbons?
Hydrocarbons containing carbon atoms in a ring structure with delocalized pi-bond electrons.
Benzene is the most common example.
What is the general formula for alkanes?
CₙH₂ₙ₊₂
Where n is the number of carbon atoms.
What are the combustion products of alkanes?
- Carbon dioxide
- Water
Complete combustion requires sufficient oxygen.
List two uses of alkanes.
- Fuels
- Solvents
Methane and propane are common examples.
Methane is the primary component of natural gas.
Fill in the Blank:
Alkanes are also known as _______ hydrocarbons.
saturated
In saturated hydrocarbons, every carbon is attached to the maximum number of hydrogen atoms possible.
Alkanes are saturated since they contain only single covalent bonds. Alkenes are alkynes are unsaturated due to presence of double and triple bonds respectively.
Which is the simplest alkene?
Ethene
(C₂H₄)
Alkenes contain a carbon-carbon double bond with the general formula; CₙH₂ₙ.
Ethene is commonly known as ethylene.
List four types of reactions that alkenes undergo.
- Addition reactions
- Elimination reactions
- Substitution reactions
- Rearrangement reactions
These reactions are driven by the presence of the pi bond.
What is the general formula for alkynes?
CₙH₂ₙ₋₂
Where n is the number of carbon atoms.
What types of reactions can alkynes undergo?
Addition reactions
They cannot undergo elimination or rearrangement reactions due to the nature of the triple bond.
Which hydrocarbon is used in welding?
Ethyne
(acetylene)
Its high energy release makes it suitable for welding.
What are the physical properties of hydrocarbons?
- Low melting points
- Low boiling points
- Insoluble in water
- No conductivity
These properties increase with molecule size.
They are insoluble in water since they are non-polar.
Alkynes have the highest boiling and melting points followed by alkenes.
What are the organic factors that affect boiling and melting points?
- Chain branching
- Chain length
- Functional groups
- Double and Triple Bonds
All of these factors must be taken into account, as they can either increase or decrease the boiling and melting points of different compounds.
How does chain branching affect the boiling point of hydrocarbons?
Branched hydrocarbons have lower boiling points than straight-chain hydrocarbons.
Branching reduces surface area and intermolecular forces (van der Waals forces).
What is a functional group?
A part of organic compounds that contains characteristic qualities that determines the chemical properties of a molecule.
Functional groups are essential for understanding the reactivity and properties of organic compounds.
They are often sites for chemical reactions.
List five functional groups.
- Alkanes
- Alkenes
- Alkynes
- Alcohols
- Ethers
These groups are crucial for naming and identifying organic compounds.
Other examples include aldehydes, ketones, carboxylic acids, esters, amides, amines, and alkyl halides.
What is the general formula for alcohols?
R-OH
Alcohols contain a carbon bound to a hydroxyl (-OH) group.
Alcohols are polar due to the hydroxyl group. These organic compounds are often soluble in water due to their polarity, although their solubility depends on the length of the chain.
List three types of alcohols.
- Primary
- Secondary
- Tertiary
The classification depends on the number of carbon atoms bonded to the carbon with the alcohol group.
What is an example of a tertiary alcohol?
Tert-butanol
(C(CH₃)₃OH)
Tertiary alcohols are less prone to oxidation than primary or secondary alcohols. The carbon is already bonded to three other carbon atoms as well as a hydroxy group, meaning that there are no free hydrogens for bonding.
How does hydrogen bonding affect alcohol properties?
Alcohols have higher boiling points than alkanes.
This also affects their solubility in water.
What is the general formula for carboxylic acids?
R-COOH
Carboxylic acids have both a carbonyl and a hydroxyl group.
They are are acidic due to the -COOH group.
They are named using the suffix -oic acid.
What are the uses of carboxylic acids?
- Producing adhesives
- Antimicrobial agents
- Solvents
- Food flavorings
Butyric acid, for example, is used for artificial butter flavor.
What is the general formula for ethers?
R-O-R’
Ethers have an oxygen atom between two alkyl groups.
They are more polar than hydrocarbons, but less polar than alcohols.
List three uses of ethers.
- Solvents in laboratories
- Anesthetics
- Fuel additives
Their moderate polarity makes them versatile.
What distinguishes ketones from aldehydes?
- Ketones: They contain a carbonyl group (C=O) located at the middle of the molecule.
- Aldehydes: They contain a carbonyl group located at the terminal carbon.
The general formula for ketones is R-CO-R’.
The general formula for aldehydes is R-CO-H.
Acetone (CH₃COCH₃) is an example of a ketone while formaldeyde (HCHO) is an example of an aldehyde.
What is the general formula for esters?
R-COOR’
Esters are derived from carboxylic acids where the hydrogen in the OH group is replaced with another R group.
The ester group (-COO-) gives esters pleasant fruity odors.
How are esters named?
The alkyl group is named first, followed by the acid component with an -oate ending.
Example: Methyl acetate (CH₃COOCH₃).
How does the ether group differ from the ester group?
- Ether has -O- group
- Ester has -COO- group
Ethers are more inert compared to esters.
What is the general formula for alkyl halides?
RX
Where R is a carbon chain and X is a halogen.
Alkyl halides are also known as haloalkanes.
The functional group is a halogen atom (F, Cl, Br, I) bonded to an alkane.
Example: Methyl chloride (CH₃Cl).
What distinguishes primary, secondary, and tertiary amines?
- Primary: One R group attached to nitrogen.
- Secondary: Two R groups attached to nitrogen.
- Tertiary: Three R groups attached to nitrogen.
This classification determines reactivity and boiling points.
What is the general formula for amides?
R-CONH₂
Amides are derivatives of carboxylic acids.
What is a common use of amides?
Production of:
- Plastics
- Pharmaceuticals
- Proteins
Example: Nylon synthesis.
What is the functional group for phenols?
An OH group attached directly to an aromatic ring.
Example: Phenol (C₆H₅OH).
Define:
arenes
Aromatic hydrocarbons with alternating double bonds in a ring.
Example: Toluene (C₆H₅CH₃).
What is the role of a phenyl group in a molecule?
It adds aromaticity.
Phenyl groups increase stability and delocalization.
What is the functional group of nitriles?
A carbon triple-bonded to a nitrogen (C≡N).
Example: Acetonitrile (CH₃CN).
What are thioethers?
Sulfur analogs of ethers.
They have the general formula R-S-R’.
Example: Dimethyl sulfide (CH₃SCH₃).
