[Charismaztex]

a)When decomposing in water, organic refuse is oxidised to form carboxylic acids. The water
becomes acidic and aquatic life is destroyed.
Which additives are suitable to remove this acid pollution?
1 calcium carbonate
2 calcium hydroxide
3 potassium nitrate

Please give a detailed explanation regarding potassium nitrate, what are its main properties?

b) Which statement explains the observation that magnesium hydroxide dissolves in aqueous
ammonium chloride, but not in aqueous sodium chloride?
A The ionic radius of the NH+
4 ion is similar to that of Mg2+ but not that of Na+.
B NH4Cl dissociates less fully than NaCl.
C The ions Na+ and Mg2+ are isoelectronic (have the same number of electrons).
D The ion NH+
4 acts as an acid.

c) Flask X contains 1 dm3 of helium at 2 kPa pressure and flask Y contains 2 dm3 of neon at 1 kPa
pressure.
If the flasks are connected at constant temperature, what is the final pressure?
A  4/3 kPa B 3/2 kPa C 5/3 kPa D 2kPa

d) Which compounds would be formed in the reaction of ethene with aqueous bromine in the
presence of sodium chloride?
1 CH2ClCH2Cl
2 CH2BrCH2Cl
3 CH2BrCH2Br

[nj_bartel]

2) LeChatlier's
4) Halogenation of an alkene mechanism