General definitions for basic concepts and hydrocarbons

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The general formula for alkanes
CnH2n+2
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An aliphatic hydrocarbon is
A hydrocarbon with carbon atoms joined together in straight or branched chains
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An alicyclic hydrocarbon is
A hydrocarbon with carbon atoms joined together in a ring structure
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A functional group is
The part of the organic molecule responsible for its chemical properties
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A homologous series is
A series of organic molecules with the same functional group but differing by CH2
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The general formula for an alkene is
CnH2n
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The general formula for an alcohol is
CnH2n+1OH
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Structural isomers are
Molecules with the same molecular formula but with different structural arrangements in space
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Stereoisomers are
Compounds with the same structural formula but with a different arrangement of atoms in space
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E/Z isomerism is
A type of stereoisomerism in which groups attatched to each carbon (in the C=C bond) may be arranged differently in space due to the restricted rotation of the C=C bond
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cis/trans isomerism is
a type of E/Z isomerism in which there is a hydrogen and a non hydrogen group on each C in the C=C bond (z= same) (E= different)
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Homolytic fission is
The breaking of a covalent bond, with one of the bonded electrons going to each atom, forming to radicals
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A radical is
A species with an unpaired electron
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Heterolytic fission is
The breaking of a covalent bond with both of the bonded electrons going to one of the atoms, forming a cation and an anion
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A nucleophile is
An atom or group of atoms that is attracted to an electron deficient centre or atom, where it donates a pair of electrons to form a new covalent bond
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An electrophile is
An atom or group of atoms that is attracted to an electron rich centre or atom, where it accepts a pair of electrons to form a new covalent bond
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An addition reaction is
A reaction in which a reactant is added to an unsaturated molecule to make a saturated molecule
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A substitution reaction is
A reaction in which an atom or group of atoms is replaced with a different atom or group of atom
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An elimination reaction
Refers to the removal of a molecule from a saturated molecule to make an unsaturated molecule
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Fractional distillation is
The separation of the components in a liquid mixture into fractions which differ in boiling point (and hence chemical composition) by means of distillation, typically using a fractioning column
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In fractional distillation, short chained hydrocarbons
Have lower boiling points so condense near the top of the column
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As chain length (in a hydrocarbon) increases, boiling point increases because
More points of contact, more van der Waals, more energy required, higher temperature
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A branched isomer has a lower boiling point than an unbranched isomer because
Fewer points of contact, fewer van der Walls, also can not pack as closely together, decreased intermolecular forces
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Cracking refers to
The breaking down of long chained saturated hydrocarbons to form a mixture of shorter chained alkanes and alkenes
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A catalyst is
A substance that increases the rate of reaction without being used up in the process
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The higher the octane number
The more efficient it burns
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Branched and cyclic alkanes are important petrol additives as they
Promote more efficient burning
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Radical substitution is
A type of substitution reaction in which a radical replaces a different atom or group of atoms
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A mechanism is
A sequence of steps showing the path taken by electrons in a reaction
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Initiation is
The first step in a radical substitution in which the free radicals are generated by ultraviolet radiation
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Propagaition is
The two repeated steps in radical substitution that build up the products in a chain reaction
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Termination is
The step at the end of a radical substitution when two radicals combine to form a molecule
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A pi bond is
The reactive part of a double bond formed above and below the plane of the bonded atoms by sideways overlap of p orbitals
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The shape of an alkene key points
Trigonal planar, 120 bond angle, electron pair repulsion (pairs of electrons repel each other as far as possible to minimise repulsion)
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In the addition of hydrogen to an alkene
Hydrogen gas and gaseous alkene are passed over a nickel catalyst at 150C
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When bromine is added to an alkene the colour change is
Orange to colourless
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Alkenes react with halogens
At room temperature
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The reaction conditions for the addition of steam to an alkene are
H3PO4, H20(steam/gas), high temp and pressure
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A curly arrow
A symbol used in reaction mechanisms to show the movement of an electron pair in the breaking or formation of a covalent bond
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Addition polymerisation
The process in which unsaturated alkene molecules add on to a growing polymer chain one at a time, to form a very long saturated molecular chain
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Other cards in this set

Card 2

Front

An aliphatic hydrocarbon is

Back

A hydrocarbon with carbon atoms joined together in straight or branched chains

Card 3

Front

An alicyclic hydrocarbon is

Back

Preview of the front of card 3

Card 4

Front

A functional group is

Back

Preview of the front of card 4

Card 5

Front

A homologous series is

Back

Preview of the front of card 5
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