chemistry paper 3 Flashcards
Show thermally stable
Calculate 🔺total from 🔺system + 🔺surroundings
If positive feasible
Temp at which reaction is feasible
🔺system = enthalpy change / temp
Thermal stability
Size of ion/charge
Ability to polarise the bond
Barium carbonate and sulphuric acid
Not soluble
Why cold water in filtration
Less soluble in cold water so dosent dissolve
Mass of electron
1/1840
how london bonds form
uneven distribution of electrons results in a temporary dipole which induces a temporary dipole on another molecule
stronger london forces
more electrons and shells of electrons so greater dipole and therefore stronger bonds
TMS and why used
(CH3)4Si
-single peak
-dosent overlap with other peaks
-low boiling temp so can easily be removed
-strong signal so only small amount needed
why e/z isomer
restricted / limited rotation (about the C=C double bond)
each carbon atom in the double bond is attached to (two)
different atoms / different groups (of atoms) / to a H (atom)
and a COOH group
acid
proton donor
becomes more negative
base
proton acceptor
becomes more positive
ammonium
NH4
drying agent
anhydrous sodium sulphate
what happens when two compounds in flame test
stronger one masks other
why is wire heated in flame tests
to remove previous sample residue
why does the fume cupboard need to be down
(window) above the safety line means the exhaust system
is not strong enough to draw in the fumes
so the toxic fumes will escape (into the laboratory)
esterfacation with carboxilic acid compared to acyl chloride
acyl chloride - irreversable
forms hcl
fast at room temp
carboxylic acid -
reversable
forms water
needs acid catalyst
why complex ions coloured
(ligand causes d orbitals to split (into 2 energy levels)
energy in the visible region absorbed to promote electrons to
higher d orbitals
the remaining light is the complementary colour emitted
dimer
bonded with dative bonds
impurities on boiling temp
decrease and makes less sharp
stronger london forces
more electrons
colours of halogens with cyclohexane
bromine -orange
iondine -purple
