3.1 Introduction to organic chemistry Flashcards
(26 cards)
What is a homologous series
A group of organic compounds with the same functional group.
What can be said about a homologous series
Each member has:
- The same functional group
- The same general formula
- Similar chemical properties
- They have gradually changing physical properties, e.g. boiling point, melting point and density.
What do functional groups determine
The physical and chemical properties of molecules.
What is a hydrocarbon and what is its general formula
- A molecule containing only carbon and hydrogen atoms.
- CnH2n+2
What is empirical formula
The simplest whole number ratio of atoms of each element in a compound.
What is molecular formula
The true number of atoms of each element in a compound.
What is general formula
A formula for the amount of atoms which all members of a homologous series follows.
What is structural formula
It shows the structural arrangement of atoms within a molecule.
What is displayed formula
It shows every atom and every bond of an organic compound.
What is skeletal formula
- Shows only the bonds in a compound and any non-carbon atoms.
- Vertices are carbon atoms.
- Hydrogen is assumed to be bonded to them unless stated otherwise.
What is an isomer
Molecules with the same molecular formula but a different arrangement of atoms within the molecule.
What are 3 ways a molecule can be arranged
- Straight chain
- Branched
- Cyclic
What is a structural isomer
Molecules with the same molecular formula but a different structural formula.
What are the 3 types of structural isomerism
- Chain
- Positional
- Functional
What is chain isomerism
- When molecules have the same molecular formula, but their longest hydrocarbon chain is not the same.
- This is caused by branching.
What is a position isomer
When the functional group of the molecule is in a different position of the carbon chain, E.g. propane-1-ol and propane-2-ol.
What are functional group isomers
- When molecules have the same molecular formula, but a different functional group, E.g. hexene and cyclohexane.
- This occurs when different functional groups result in the same molecular formula.
- The isomers have different chemical properties as they have different functional groups.
What are stereoisomers
Molecules that have the same atoms connected to each other, but the atoms are differently arranged in space.
When does stereoisomerism occur
- If there is a double bond present (means the molecule cannot rotate, so 2 different molecules can be produced).
- When there are at least 2 different groups bonded to the carbon atoms around the double bond.
What nomenclature is used for stereoisomers
E/Z isomerism.
What is an E isomer
They have their functional groups on opposite sides of the double bond.
What is a Z isomer
They have their functional groups on the same side of the double bond (‘zame zide’).
How do you determine the priority for E/Z isomers
- The first atom which is directly bonded to the carbon with the double bond with the higher Ar has the higher priority.
- If they have the same priority, you look at the Ar of the atom directly bonded to that atom.
What rules are followed in nomenclature
- The highest priority group is always given the lowest number.
- Additional atoms (e.g. Cl or F) are always written in alphabetical order.
