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Chemsitry A Level > Key Words > Flashcards

Flashcards in Key Words Deck (37):
1

Ligind

Molecule or anion with a lone pair of electrons that can form a dative covalent bind with a central metal cation.

2

Pair of optical isomer

2 non superimposable mirror images

3

Electrophile

Positively/ partially positively charged species (no line pair)-can break a double bond

4

Nucleophile

Partially/fully negatively charged species that donates electrons to have a positive charge= forms a covalent bond

5

Year 1 mechanisms

Nucleophilic substitution-reaction with water/hydroxide ions

Electrophilic addition-bromine across a double bond

6

Year 2 mechanisms

Electrophilic substitution-eg swapping a H in a benzene ring

Nucleophilic addition-breaking double O bonds in carbonyls

7

Electron donating group

Pushed onto 2,4,6 positions
Lone pair delocalises into the ring
More reactive than benzene in electro sub

Eg OH and NH_2

8

Electron withdrawing groups

-3,5 positions
Pulls electrons away from group
Less reactive than benzene in electro sub

Eg NO_2

9

Aliphatic

Straight chained, branches or non aromatic rings

10

Alicyclic

Alicyclic compound arranges in a non aromatic ring with side chains

11

Aromatic

Compounds that contain an arene (benzene) ring

12

Co-polymerisation

Mix up of different monomers (more than 2)

13

Thermosetting polymers

Once moulder do not soften again eg tyres

14

Thermoplastic polymer

Becomes pliable/mouldable at a specific temperature and solidified upon cooling

15

Amine

H of NH_2 group replaces by a carbon

16

Amide

N attached to C=O

17

Nitrile

R-CN

18

Lattice enthalpy

1 mole of ionic compound formed from gaseous ions in standard conditions

19

Enthralled of solution

1 mole of solute dissolves in a solvent (water)

20

Enthalpy of ionisation

1 electron removes from each atom in 1 mole of gaseous atoms

Ea is the reverse

21

Enthalpy of formation

1 mole of compound formed from elements in standard states and conditions
(Products)-(reactants)

22

Exothermic

Heat energy transferee to the surroundings (bond making)

23

Endothermic

Heat energy is absorbed from the surroundings (bond breaking)

24

Standard enthalpy of combustion

When 1 mole of substance is completely burned in O2 under standard conditions

25

Standard enthalpy of neutralisation

When acid and base react in standard states to form 1 mole of water

26

Bond enthalpy

Average energy required to break 1 mole of binds in gaseous molecules

27

Trends in group 2

Reactivity increases down the group

First ionisation energy decreases

Oh increased down the group and alkability increases

28

Ka=[H+]2/[HA] assumptions

HA equilibrium= initial
All H+ from HA
[H+]=[A-]

29

Buffer assumptions

[weak acid] equilibrium=initial
All conjugate base from salt not acid

30

Buffer
Add H+

Add OH-

H+= shift to left

OH-= shift to right to restore H+
(Reacts to produce water)

31

Examples bidentate liginds

C_2O_42-

H_2NCH_2CH_2NH_2

32

Periodicity
Down a group

Atomic radius increases=increased shielding

Increase nuclear charge rules out

First ionisation energy decreases

33

Periodicity
Across period

Atomic radius decreases

Shielding stays the same

Higher nuclear charge=strong attraction

First ionisation energy increases

34

Qualitative analysis

1-carbonate-dilute nitric acid

2-Sulphate test-add barium

3-halide test-add silver nitrate

4-test for cations-NaOH=produce ammonia gas

35

Primary cell

Non rechargeable
Low current
Long storage
Alkaline based

36

Secondary cells

Rechargeable
Lead-acid nickel-calcium lithium-ion

37

Fuel cells

Fuel react with O_2
Operate continuously
Not have to be recharged

Hydrogen fuel cell- +1.23V
Acid or alkali
H_2 +1/2 O_ = H_2O