Chemistry difficulties?

Question

I'm having problems with all these weird products in Chem problems. I don't see how I could have predicted these. Can someone explain the logic behind these to me. Here are a few examples.

Pure phosphorous burned in air.
P + O2 yields P4O10
Why?

Access concentrated HCl is added to 1.0M solution of CoCl2.
HCl + CoCl2 yields H2 + CoCl3
What the %^#^!?

Solid cesium oxide is added to water.
Cs2O + H2O yields 2Cs + 2OH-
Huh?

A solution of potassium hydroxide is added to solid ammonium chloride.
I don't even know about this one.

And what's up with sulfuric acid?
H2SO4 + anything yields whatever it wants apparently.

I seriously need help.

Answer 1

Chemistry is strange, and not everything is intrinsically predictable. Phoshorous reacts with oxygen to form an oxide with -P-O-P- type bonds. Each P can form 4 such bonds (only two are shown above). The molecule exists as a pyramid with a triangular base with a P atom at each corner. Each P has 4 bonds with an oxygen, and each oxygen bonds between 2 phosphorous atoms.

The second case is a "redox" reaction. In this case, the oxidation number of hydrogen is reduced from +1 to 0 (all elemental forms have 0 oxidation number), while Cobalt ion goes from +2 to +3 oxidation number.

The reaction for cesium is incorrect. When the oxide dissolves in water, Cs+ ion exists along with hydroxyl ion (OH-). This is a strong base in water.

A strong base like KOH will react with an ammonium salt (here, NH4+Cl-) to liberate the ammonia. The remaining entities, H+ and Cl- will form KCl and water with KOH.

Sulfuric acid can act as a strong acid, but it can also act as an oxidizing agent, so you can get an assortment of products in reactions.

Answer 2

Because it takes 4 P's to burn with 10 O's ( 5 O2, really )

4P + 5O2 > P4O10

Sort of like that.

And an acid base reaction does not yeild any thing it wants. Strong acids, H2SO4 and strong bases,KOH produce a salt and water. Thus.

2KOH + H2SO4 > K2SO4 + 2H2O