Pack 2B definitions Flashcards Preview

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Flashcards in Pack 2B definitions Deck (24):
1

structural isomers

molecules with the same molecular formula but different structural arrangement of atoms

2

stereoisomers

compounds with the same structural formula but a different arrangement of atoms in space

3

E/Z isomerism

a type of steroisomerism in which different groups attached to each carbon of a c=c double bond may be arranged differently in space due to the restricted rotation of the double bond

4

cis- trans isomerism

is a special type of E/Z isomerism in with there is a non-hydrogen group and a hydrogen on each C of a C=C double bond.
The cis isomer (Z isomer) has has the H atoms on each carbon on the same side .
The trans isomer (E isomer has the H atoms on each carbon on different sides)

5

homolytic fission

the breaking of a covalent bond, with one of the bonded electrons going to each atom forming two radicals.

6

radical

a species with an unpaired electron

7

heterolytic fission

the breaking of a covalent bond where both of the bonded electrons going to one of the atoms forming a cation and a anion.

8

nucleophile

an atom of a group of atoms that is attracted to an electron deficient center or atom where it donates a pair of electrons to form a new covalent bond

9

electrophile

an atom or group of atoms that is attracted to an electron rich atom or center and accepts a pair of electrons to form a new covalent bond

10

addition reaction

a reaction in which a reactant is added to an unsaturated molecule to make a saturated molecule

e.g. ethene + bromine (electrophile) ------> 1,2- dibromoethane

11

substitution reaction

a reaction in which an atom or groups of atoms is replaced with a different atom or group of atoms

e.g. bromoethane + hydroxide ion (nucleophile) ---> ethanol + bromide ion

12

elimination reaction

the removal of a molecule from a saturated molecule to make an unsaturated molecule

e.g. ethanol------>ethene + water

13

radical substitution

a type of substitution reaction in which a radical replaces a different atom or group of atoms

14

mechanism

a sequence of steps showing the path taken by electrons in a reaction

15

Initiation

the first step of a radical substitution in which free radicals are generated by ultraviolet radiation

16

Propagation

the two repeated steps in radical substitution that build up the products in a chain reaction

17

Termination

the step at the end of a radical substitution when two radicals combine to form a molecule

18

a Pi bond

the reactive part of a double bond formed above and below the plane of bonded atoms by the sideways overlap of p orbitals.
fixes the carbon atoms in position at either end of the double bond preventing rotation.

19

a sigma bond

bond formed directly between two carbon atoms by the overlap of orbitals

20

polymer

a long molecular chain built up from monomers

21

monomer

small molecule that combines with many other monomers to form a polymer

22

addition polymerisation

the process in which unsaturated alkane molecules (monomers) add on to a growing polymer chain one at a time to form a very long saturated molecular chain.

23

addition polymer

a long molecular chain formed by repeated addition reactions of many unsaturated alkene molecules

24

biodegradable material

material that is broken down naturally in the environment by organisms