Definitions

HideShow resource information
Functional group
an atom or group of atoms that determines the chemical properties of an organic compound
1 of 50
Homologous series
a series of compounds containing the functional group/ general formula where members of the series differ by a -CH2- unit
2 of 50
molecular formula
the formula showing the actual ratio of atoms in a compound
3 of 50
empirical formula
the formula showing the simplest whole number ratio of elements
4 of 50
general formula
the algebraic formula that represents all members of a homologous series
5 of 50
structural formula
the formula that shows how the atoms are joined to each other
6 of 50
displayed formula
shows all the covalent bonds and all the atoms in a compound
7 of 50
skeletal formula
shows the carbon-carbon bonds as lines, does not show any carbon or hydrogen atoms but does show the functional groups
8 of 50
structural isomerism
this is when substances have the same molecular formula but different structural formula
9 of 50
stereoisomers
compounds that have the same molecular and structural formula but different arrangements of their atoms in space
10 of 50
E/Z isomers
occurs in compounds having C=C bonds where there are two different groups on each carbon of the double bond
11 of 50
hydrocarbon
compounds composed of hydrogen and carbon only
12 of 50
saturated
compounds having only single bonds between carbons
13 of 50
unsaturated
compounds containing at least one carbon-carbon multiple bond
14 of 50
fractional distillation
separation of mixtures based on boiling point differences
15 of 50
fraction
a mixture of liquids having boiling points which are close in value
16 of 50
reflux
technique that allows us to perform a reaction at boiling point without evaporation of the reactants. A reflux condenser is employed to condense vapours back into the reaction vessel
17 of 50
biofuel
fuels derived from recently dead biological material i.e. fuels from processing crops
18 of 50
cracking
the decomposition of long chain alkanes into shorter chain alkanes and alkenes
19 of 50
reforming
the conversion of alkanes into cyclic alkanes and alkenes
20 of 50
isomerisation
the conversion of straight chain alkanes into branched alkanes
21 of 50
free radical
species having an unpaired electron
22 of 50
homolytic bond fission
when a covalent bond breaks evenly so that each of the bonded atoms retains one electron from the bond. this produces free radicals
23 of 50
heterolytic bond fission
when a covalent bond breaks unevenly so that one of the bonded atoms retains both electrons from the bond. produces a positive and negative electron
24 of 50
electrophile
electron pair acceptor (positive partial charge)
25 of 50
nucleophile
electron pair donor (partial negative with lone pair)
26 of 50
addition reaction
the joining of two molecules to form a single product molecule
27 of 50
substitution reaction
an atom (or group of atoms) is replaced by another atom (or act)
28 of 50
elimination reaction
when a small molecule is removed from a larger one
29 of 50
enthalpy changee
an energy change measured under standard conditions
30 of 50
standard conditions
temperature 298K (25*C), pressure 110kPa (1 atmosphere); solutions 1molddm-3
31 of 50
exothermic reactions
reaction that releases heat energy to the surroundings (AH-) e.g. combustion, respiration
32 of 50
endothermic reaction
reaction that absorbs heat energy from the surroundings (AH+) e.g. thermal decomposition, photosynthesis
33 of 50
standard enthalpy of reaction
enthalpy change when the amounts shown in a reaction equation react under standard conditions
34 of 50
standard enthalpy of formation
enthalpy change one one mole of a compound is formed from its elements under standard conditions
35 of 50
standard enthalpy of combustion
enthalpy change when one mole of substance is completely burnt in excess oxygen under standard conditions
36 of 50
specific heat capacity
the heat energy required to raise the temperature of 1 gram of substance by 1*C
37 of 50
Hess's law
the enthalpy change for a reaction is independent of the route taken, provided the initial and final conditions are the same
38 of 50
bond enthalpy
the average enthalpy change when 1 mole of bond of a particular type are broken in gaseous molecules
39 of 50
collision theory
for a reaction to occur successfully, particles must collide with sufficient energy(>Ea)&be in correct orientation.temp increase=more have E
40 of 50
activation energy
minimum energy required for a successful reaction to occur
41 of 50
catalyst
a substance which increases the rate if a chemical reaction without being used up in the process. They work by lowering activation energy, so more particles have E>Ea
42 of 50
heterogenous catalyst
a catalyst that is in a different state to the reactants e.g. Pt/Rd/Pd in catalytic conversion or Fe in haber process
43 of 50
homogenous catalsy
a catalyst that is in the same state (phase) as the reactants e.g. chlorine radicals in ozone depletion
44 of 50
le chatelier's principle
if any of the conditions of a system at equilibrium are change, the system will adjust its self in order to minimise the change
45 of 50
dynamic equilibrium
rates of forward and reverse reactions are equal and so concentrations of all the species present remain constant. Cloose system required.
46 of 50
Position of equilibrium
Qualitative description of the amount of products to starting materials in the equilibrium mixture
47 of 50
Temperature changes
increase= shifts POE in the endothermic direction. decrease= shifts POE in the exothermic direction
48 of 50
Pressure changes (gaseous systems)
increase=shifts POE in direction that leads to fewest gas moles. decrease=shifts POE in direction that leads to the most gas moles
49 of 50
Catalysts
have no effect on POE or yield obtained- they speed up both forward and reverse reactions equally
50 of 50

Other cards in this set

Card 2

Front

Homologous series

Back

a series of compounds containing the functional group/ general formula where members of the series differ by a -CH2- unit

Card 3

Front

molecular formula

Back

Preview of the front of card 3

Card 4

Front

empirical formula

Back

Preview of the front of card 4

Card 5

Front

general formula

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Unit 2 resources »