~急一堆化學問題

(1)
potassium + oxygen → potassium oxide
4K + O2 → 2K2O

(2)
No, conc. sulphuric acid is not strong enough to oxidize Fe to Fe3+
it can just oxidize Fe to Fe2+

(3)
it has to depend on which gas
H2 is insoluble in water
NH3 is soluble in water

(4)
for reduction of MnO4-
MnO4- + 8H+ + 5e- → Mn2+ + 4H2O
as you can see, from the left-hand-side of the equation
MnO4- will only reduce itself in the presence of H+ ions
so the reduction of MnO4- should carry out in acidic medium which contain H+ ions
HNO3 is also an oxidizing agent
it will react with the reactant instead of what MnO4- do
HCl contains Cl- ions, which may oxidized to Cl2 by MnO4-
so it is also not appropriate

(5)
When acids undergo neutralization, they all perform like a typical acid
please pay attention
acids + carbonates is not neutralization
only acids + alkalis is called neutralization
and when acids react with carbonates, they all perform like a typical acid

(6)
add equal amount of nitric acid followed by a few drops of silver nitrate solution
Ag+ + Br- → AgBr
AgBr ppt. which is cream in colour formed
Ag+ + I- → AgI
AgI ppt. which is yellow in colour formed

(7)
Yes
OCl- + Cl- + 2H+ → Cl2 + H2O
OCl- and Cl- come from chlorine bleach
H+ comes from acid

(8)
strong metallic bond
or the attractive force between the positive nucleus and sea of delocalized electrons

(9)
Saturated solution is a solution which contain maximum amount of solute in specified temperature.

(10)
It can decolourize acidified KMnO4 (purple to colourless)
It can decolourize bromine in bromine water (brown to colourless)
It can decolourize bromine in 1,1,1-trichloroethane (orange to colourless)

1. potassium oxide
2. Yes
3. Inorganic gases that dissolve in water are all acidic gas or alkaline gas
Organic gases : depends on each gas
4. On reaction, MnO4- reduces itself and the reaction requires the presence of H+ ions.
HNO3 is not used since it is also oxidizing
HCL is not used as Cl- ions may be oxidized to form chlorine gas.
5. Yes. Both of them act as typical acid when reacting with carbonate.
6. Add acidified silver nitrate soultion.
AgBr -- pale yellow p.p.t.
AgI -- yellow p.p.t.
7. Yes
8. Strong electrostatic force
9. The amount of solute in the solvent is MAXIMUM.
No more solute can dissolve in a saturated solution.
10.It decolourizes acidified KMnO4.