paper 3 chem mistakes

enthalpy of lattice dissociation

the enthalpy change, when one mol of a solid ionic compound DISSOCIATES FULLY into its gaseous ions

main difference of value of enthalpy of solution

HEAT GAIN FROM SURROUNDINGS

or incomplete dissolving

test for AL3+

Addition of NaOH in excess, gives white ppt, but redissolves in EXCESS

why does damp red litmus paper go blue for test for ammonia

shows presence of NH4+

definition of steroisomers

1) Same molecular formula

2) Different spatial arrangement of ATOMS

why can … not experience e/z isomerism

two of the same groups on one of the C=C

quicker formation of ppt for halides and silver

carbon halogen bond strength decreases down the group

why is the reaction fastest at the start

1) high conc of reactants

2) more frequent successful collisions

define autocatalyst

product of the reaction catalyses the reaction

why is reaction slow at first, then goes quickly

1) negative ions repel

2) High activation energy

3) attraction between oppositely charged ions / negative reactant ion(s) and positive catalyst / Mn2+ / Mn3+

equation for Mno4 reaction and C2O4

4 Mn2+ + MnO4 – + 8 H+ → 5 Mn3+ + 4 H2O

2 Mn3+ + C2O4 2– → 2 Mn2+ + 2 CO2