UNIT 2 - Homologous Series Flashcards
what is the Homologous series?
a family of compounds with the same general formula and similar chemical properties that show a gradual change in physical properties
what do alkanes, alkenes, and cyloalkanes, all belong to?
they all belong to different homologous series
what are hydrocarbons?
molecules which consist of hydrogen and carbon atoms only
what is molecular formual?
formula which shows the number of atoms of the different elements which are present in one molecule of a substance
what is full structural formula?
a 2D drawing of a 3D molecule, it shows the atoms present and the position of the covalent bonds
what is shortened structural formula?
formula which shows the position of the atoms in the molecule without showing the bonds
what are the first 8 alkanes in order?
methane, ethane, propane, butane, pentane, hexane, heptane, and octane
what are alkanes?
-a subset of saturated hydrocarbons,
-all end in -ane
-only contain carbon to carbon single bonds
-have the general formula Cₙ H₂ₙ + ₂
-are insoluble in water
-are commonly used as fuels
what is are isomers?
molecules which have the same molecular formula but different structural formula
what are branches with 1-methyl???
it is a bend in the chain, not a branch
what is a physical property?
something which can be observed or measured
what is a boiling point?
the temperature at which a liquid turns into a gas
what happens as the number of carbon atoms increase?
the boiling increases
what are intermolecular forces?
they are small forces of attraction that exist between molecules
what is a chemical property?
its a property that becomes evident during a chemical reaction
what is flammability?
it is ease of combustion
what happens as chain length increases?
the flammability decreases
why are smaller alkanes more flammable?
because they can mix with oxygen in the air
what do alkanes undergo with the oxygen in the air?
combustion
what is the test for water?
turns cobalt chloride from blue to pink
in a plentiful supply of oxygen, what do alkanes burn to produce?
carbon dioxide and water
in a limited supply of oxygen, what do alkanes burn to produce?
carbon, carbon monoxide and water
what is a saturated hydrocarbon?
it is a hydrocarbon in which all carbon-to-carbon double bonds are single bonds
what are cycloalkanes?
-a subset of saturated, cyclic hydrocarbons
-all end in -ane
-have the general formula Cₙ H₂ₙ
what happens as cycloalkanes increase in size?
their melting and boiling points increase
what happens as the size of a molecule increases?
the number of intermolecular forces increase, and the amount of energy required to break the intermolecular forces increases
are cycloalkanes reactive?
no, with the exception of combustion
what do cycloalkanes burn to produce?
carbon dioxide and water
what is the main use of cyclohexane
to make nylon
what are cycloalkanes in water?
they are immiscible in water, and they are a good solvents for other compounds which are insoluble in water
what are alkenes?
-a homologous series of unsaturated hydrocarbons,
-all end in -ene
-contain a reactive carbon-to-carbon double bond
-have the general formula Cₙ H₂ₙ
-are used to make polymers and alcohol
-are insoluble in water
what must the name of the alkene indicate?
the position of the double bond (only after propene)
what is an unsaturated hydrocarbon?
a hydrocarbon in which there is at least one carbon-to-carbon double bond
do cycloalkanes and alkanes decolourise bromine water?
no
do cycloalkanes and alkanes undergo addition reactions?
no
do alkenes decolourise bromine water?
yes
do alkenes undergo addition reactions?
yes
what are some features of plastics?
THEY ARE:
-light
-watertight
-flexible
-able to be moulded
-good insulators of heat
-durable
what are some features of natural materials?
THEY ARE:
-biodegradable
-made from renewable resources
-can be expensive
-not durable
what does biodegradable mean?
able to rot by natural decay
what are monomers?
small molecules which can join together to produce a very large molecule
what are polymers?
very large molecules which are formed by the joining of many smaller molecules (monomers)
what is polymerisation?
the process whereby a polymer is formed
