11 - Organic Chem Flashcards
Define hydrocarbon
compound containing only carbon and hydrogen
Define saturated
molecule contains only single bond
Define unsaturated
molecule contains carbon-carbon multiple bonds
Define homologous series
a family of compounds with similar chemical properties whose successive members differ by CH2
Define functional group
the part of an organic molecule that is largely responsible for the molecules chemical properties
Define molecular formula
• Shows the number of each type of atom present in one molecule of a compound
Define empirical formula
• Shows the simplest whole number ratio of the atoms present
What does the neither the molecular or empirical formula show
information about the structure of a molecule
Define general formula
• Simplest algebraic formula for any member of the homologous series
General formula for alkanes
General formula for alkenes
General formula for alcohols
General formula for carboxylic acids
General formula for ketones
What is structural formula
• Shows how the atoms are arranged in a molecule and which functional groups are present
• Doesn’t show single bonds unlike displayed formula
What is the skeletal formula
Simplified organic formula
How to draw the skeletal formula
• Remove – all carbon/hydrogen labels + any bonds to hydrogen
• Leaving – a line representing a single bond // each corner is a carbon // any functional group
Draw the skeletal formula
What are the three types of hydrocarbons
• Aliphatic
• Alicyclic
• Aromatic
What are aliphatic hydrocarbons
carbons are joined to each other in unbranched or branched chains
What are Alicyclic hydrocarbons
carbon atoms are joined to each other in ring structures
What are aromatic hydrocarbons
some or all of the carbon atoms are found in a benzene ring
Types of aliphatic hydrocarbons
• Alkanes
• Alkenes
• Alkynes
What are alkynes
contain at least one carbon – carbon triple bonds
IUPAC rules for nomenclature
• Identify the suffix – functional group
• Identify the longest continuous chain
o If two are the same length, the one with the more branches = longest
• Number the carbons, starting from the end which gives branches the lowest number
• Identify any side chains (alkyl groups) or other functional groups + identify which number carbon on the parent chain they are on
When to use commas in naming
Between two numbers
When to use dashes in naming
Between a number and a letter
How to make acyclic alkanes
• Same rules
• BUT use the prefix ‘cyclo’ in front of stem
Functional group name + example molecule of halo alkenes
Functional group name + example molecule of alcohols
Functional group name + example molecule of aldehyde
Functional group name + example molecule of ketone
Functional group name + example molecule of carboxylic acid
Order of priority of naming
Name
Propan - 2 - ol
Name
Name
Name
Name
Name
Name
Name
Name
Define isomers
molecules with the same molecular formula but in which the atoms are arranged in a different way
Two types of isomerism
Structural and stereoisomerism
Define structural isomerism
have the same molecular formula, but different structural formulae
Define stereoisomerism
have the same structural formula, but different arrangements of atoms in space.
Types of structural isomerism
Chain isomerism /positional isomerism / functional groups isomerism
What is chain isomerism
• the carbon chain is arranged differently.
What does chain isomerism result in
The isomers will have similar chemical properties, but different physical properties.
What is positional isomerism
• the functional group is attached to a different carbon atom
What does positional isomerism result in
The isomers will have similar chemical properties, but different physical properties.
What is functional group isomerism
• contain different functional groups and so are members of different homologous series.
What does functional group isomerism result in
different chemical properties and physical properties.
Example of functional group isomerism
both alcohols and ethers have the general formula CnH2n+2O so they may be functional group isomers
Define covalent bond
a shared pair of electrons between two atoms
How are covalent bonds broken
homolytic fission or heterolytic fission
What is homolytic fission
• each atom takes one of the electrons from the bond
What does homolytic fission result in
• Each atom now has a single unpaired electron = A radical
Define radical
Species with an unpaired electron
Example of homolytic fission
What is heterolytic fission
• One of the atoms take both electrons from the bond
What does heterolytic fission result in
• The atom with both electrons becomes a negative ion
• The atom that did not take the electrons becomes a positive ion
Example of heterolytic fission
Describe the difference between homolytic and heterolytic fission, using suitable examples (4 marks)
What are the three types of reactions
• Addition, substitution, elimination
What is addition reaction
• two reactants join together to form one product
Example of an addition reaction
but-2-ene + water -> butan-2-ol
o A water molecule is added to an unsaturated alkene
o Breaking the double bond
o Forming a single, saturated compound
What is a substitution reaction
• An atom/group of atoms is replaced by a different group/atom
Example of a substitution reaction
1-bromobutane + OH- -> butan-1-ol + Br-
o An OH- ion (alcohol functional group) replaces Br- ion (bromine functional group)
What is an elimination reaction
small molecule is removed from a compound, thus one reactant molecule forms two products.
Example of an elimination reaction
ethanol - > ethene + water
o an acid catalyst helps remove a water molecule from an alcohol
o Removal of a group from a carbon means that the carbon must form a double bond (to fulfil the 4 bonds that it wants to form)
What are curly arrows used for
to show the movement of electron pairs when bonds are broken/made
Draw the heterolytic fission of carbon - bromine bond in bromoethane
