Paper 3-2021 Flashcards
(18 cards)
Why polyesters are biodegradable
Polyesters have c-o/c=o bond and polar whereas polyalkebes are non polar. Polyesters susceptible to nucleophilic attack/can be hydrolysed
Safety Precautions when filling burette
Fill below eye level
Precautions when dissolving solid
Wash hands/wear gloves
2 practical steps before reading initial burette reading
Fill jer space
Remove funnel
Safety hazard with KCN and why KCN used over HCN
Toxic gas produced
HCN is weak acid/partly ionises
Sodium bromide with conc H2SO4 to form bromine and observation
2NaBr+2H2SO4–> Na2SO4+Br2+H2O+SO2
Br is an fumes/solution
Why AgNO3 used
Removes CO32- ions that could produce ppt with AgNO3
Why apparatus not safe with reflux
Flask not clamped
Bung will cause build up of gas
One additional reagent need to form propanone acid
Sulfuric acid/H3PO4
Two mistakes in apparatus
Water flowing wrong way
Thermometer not needed
Distinguish ca from alcohol
Na2CO32-
Effervescent
No change
What doesn’t involve absorption of uv
Ionisation of a molecule in mass spectrometer
What statement about chlorine ions are false
Forms an octahedral cobalt complex when aq co reacts with excess bromide solution
What statement about inorganic ionic compound always correct
Forms giant structures
Species has lp of e on central atom
SO2
Molecule are all atoms in same plane
C6H5Cl
Permanent dipole dipole
NH3
Which compound needs greatest amount of oxygen for complete combustion of 1mol of compound
Ethanol
