topic 10/20 Flashcards
define a homologous series
a series of compounds of the same family, with the same general formula, which differ from each other by a common structural unit (CH2, methylene group)
explain the trend in boiling points and density of members of homologous series
boiling point/density increases as length of carbon chain increases:
- molecular mass increases/no of C atoms increases
- London forces increase as the molecules get bigger
describe and explain the trend in solubility of members of a homologous series
less soluble as homologous series is ascended:
hydrocarbon chain is non-polar (hydrophobic) and as no of carbons increase, this increases the percentage of the molecule that is unattractive to water.
what does the solubility of a compound in water depend on?
solubility in water depends on the ability of the water molecules to attract dipoles in the organic compound.
describe physical and chemical properties of homologous series
- physical properties change gradually as the length of the carbon chain increases
- similar chemical properties
general formula of alkanes
CnH2n+2
general formula for alkenes
CnH2n
general formula for alkynes
CnH2n-2
general formula for ketones
CnH2nO
general formula for alcohols
CnH2n+1OH
general formula for aldehydes
CnH2n+2
general formula for carboxylic acids
CnH2n+1COOH
define an empirical formula
the simplest ratio of the atoms within a molecule of the compound
define the molecular formula
shows the actual number of atoms of each type in the molecule
define the structural formula
shows the actual arrangement of the atoms in a molecule by drawing the bonds as lines between letters representing the atoms
define a skeletal formula
each carbon is represented by an angle, or termination in a line and the hydrogen atoms are just assumed
state the two ways that structural formulae can be represented.
- full format
- condensed format
describe alkanes as a class of organic compounds
saturated hydrocarbons
describe alkenes as a class of organic compounds
unsaturated hydrocarbons- carbon and hydrogen atoms with one or more carbon-carbon double bond in their chemical structure
describe alkynes as a class of organic compounds
organic molecules made of the functional group carbon-carbon triple bonds
describe halogenoalkanes as a class of organic compounds
organic compounds that contain one or more halogen atom (chlorine, bromine, fluorine, or iodine) attached to a carbon atom in an alkane molecule
- RX, where R=alkyl group, H= halogen
describe alcohols as a class of organic compounds
one or more hydroxyl (―OH) groups attached to a carbon atom of an alkyl group (hydrocarbon chain).
describe ethers as a class of organic compounds
characterized by an oxygen atom bonded to two alkyl or aryl groups
R−O−R′
describe aldehydes as a class of organic compounds
a carbon atom shares a double bond with an oxygen atom, a single bond with a hydrogen atom, and a single bond with another atom or group of atoms
R−CH=O