Organic Chemistry Definitions Flashcards
What are Hydrocarbons?
These are molecules (covalent compounds) contain atoms of carbon and hydrogen only
What are Saturated Molecules?
These are molecules which contain only single bonds (no double or triple bonds)
What are Unsaturated Molecules?
These are molecules which contain at least one double or triple bond (between carbon atoms)
What are Aliphatic Molecules?
These are molecules which contain carbon atoms arranged in a chain, wether the chain is straight or branched
What are Aromatic Molecules? (Year 13)
These are molecules which contain at least one ring of carbon atoms over which electron density is delocalised
What is an Empirical Formula?
This gives the simplest (whole number) ratio of atoms of each element present in the molecule
What is a Molecular Formula?
This gives the actual number of atoms of each element present in the molecule/compound
What is a Structural Formula?
This shows the unique arrangement of atoms in a molecule in a simplified form, without showing all the bonds. Each carbon is written separately.
Shows us how the atoms are arranged |does not show the bonds present
What is a Displayed Formula?
This is a diagram which shows every atom and bond in the molecule, with stick lines representing chemical bonds.
Shows us the relative position of each atom including covalent bonds
Does not show us Bond Angles
What is a Homologous Series?
This is a group of molecules which have similar properties and which conform to a general formula.
* They show a gradual change in physical properties (e.g. boiling point)
* Each member differs by CH2 from the last
* same chemical properties
A Homologous series of organic molecules have the same functional group but each successive member had an additional CH₂
What is a General Formula?
A formula which can represent all the aliphatic members of a particular homologous series
The simplest algebraic formula for a member of a homologous series
What is an Alkyl group?
A Hydrocarbon chain, CnH2n+1, sometimes represented by the letter R
What is a Functional Group?
The atom or group of atoms that determines the molecule’s chemical properties.
The part of a molecule which determines how it acts
Problems with the Molecular Formula:
- Does not give us any information on the structure of the molecule
- Different compounds can have the same molecular formula
What is a Skeletal Formula?
shows the simplified organic formula, shown by removing hydrogen atoms from alkyl chains, leaving just a carbon skeleton and associated functional groups.
