Key Words Flashcards
Ligind
Molecule or anion with a lone pair of electrons that can form a dative covalent bind with a central metal cation.
Pair of optical isomer
2 non superimposable mirror images
Electrophile
Positively/ partially positively charged species (no line pair)-can break a double bond
Nucleophile
Partially/fully negatively charged species that donates electrons to have a positive charge= forms a covalent bond
Year 1 mechanisms
Nucleophilic substitution-reaction with water/hydroxide ions
Electrophilic addition-bromine across a double bond
Year 2 mechanisms
Electrophilic substitution-eg swapping a H in a benzene ring
Nucleophilic addition-breaking double O bonds in carbonyls
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
Electron withdrawing groups
-3,5 positions
Pulls electrons away from group
Less reactive than benzene in electro sub
Eg NO_2
Aliphatic
Straight chained, branches or non aromatic rings
Alicyclic
Alicyclic compound arranges in a non aromatic ring with side chains
Aromatic
Compounds that contain an arene (benzene) ring
Co-polymerisation
Mix up of different monomers (more than 2)
Thermosetting polymers
Once moulder do not soften again eg tyres
Thermoplastic polymer
Becomes pliable/mouldable at a specific temperature and solidified upon cooling
Amine
H of NH_2 group replaces by a carbon
Amide
N attached to C=O
Nitrile
R-CN
Lattice enthalpy
1 mole of ionic compound formed from gaseous ions in standard conditions
Enthralled of solution
1 mole of solute dissolves in a solvent (water)
Enthalpy of ionisation
1 electron removes from each atom in 1 mole of gaseous atoms
Ea is the reverse
Enthalpy of formation
1 mole of compound formed from elements in standard states and conditions
(Products)-(reactants)
Exothermic
Heat energy transferee to the surroundings (bond making)
Endothermic
Heat energy is absorbed from the surroundings (bond breaking)
Standard enthalpy of combustion
When 1 mole of substance is completely burned in O2 under standard conditions
Standard enthalpy of neutralisation
When acid and base react in standard states to form 1 mole of water
Bond enthalpy
Average energy required to break 1 mole of binds in gaseous molecules
Trends in group 2
Reactivity increases down the group
First ionisation energy decreases
Oh increased down the group and alkability increases
Ka=[H+]2/[HA] assumptions
HA equilibrium= initial
All H+ from HA
[H+]=[A-]
Buffer assumptions
[weak acid] equilibrium=initial
All conjugate base from salt not acid
Buffer
Add H+
Add OH-
H+= shift to left
OH-= shift to right to restore H+
Reacts to produce water
Examples bidentate liginds
C_2O_42-
H_2NCH_2CH_2NH_2
Periodicity
Down a group
Atomic radius increases=increased shielding
Increase nuclear charge rules out
First ionisation energy decreases
Periodicity
Across period
Atomic radius decreases
Shielding stays the same
Higher nuclear charge=strong attraction
First ionisation energy increases
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
Primary cell
Non rechargeable
Low current
Long storage
Alkaline based
Secondary cells
Rechargeable
Lead-acid nickel-calcium lithium-ion
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
