[rajm95]

We were given a solid sample(4g) at school, and we are supposed to find what compounds it has and cuantify the amounts of each.
We were told that the substances it may have are the next:
Copper II    Aluminium III    Iron III            iodides (I-)              Benzoic acid
Zinc II        Cobalt III          Lead II            bromides (Br-)         Caffeine
Silver I       Iron II              Barium II        acetylsalicylic acid

What we know already:
Acid-Base Reactions
Precipitations
Spectrofotometry
Complex Formations
Redox Reactions

What we have to do
Desing the experiment that will allow to tell us if we have or not the compounds

Do you have any tips to start with, a method to follow, or some advice??

we are students that have only got chemistry I, and we are currently studing analitical chemistry

[marquis]

A good place to start is with standard methods for waste water analysis.

In the past, I used the standard methods of analysis from the American
Waste Water Association.  They usually have a range of methods, from
base chemical to involved instrumental procedures.  See if your library
has these on hand.

Good luck.