[Alberto_Kravina]

Just out of curiosity: Is there any definition for "diluited" and "concentrated"

I don't think so, in our lab we use 2M solutions as diluited solutions and satured solutions (e.g. satured HCl-solution) as concentrated.

[samuel_shafek]

dear alberto,
how do you do ?
the terms "diluted" and "concenterated" are relative terms
they may have exact meaning "concenteration", for example conc. sulphuric-by covention-means 98% concentration and so on.
you -by mentioning the term "saturated" see confused ,as saturation is condion in which the solution cantain maximum amount of solute which may -in some cases - spairingly soluble electrolyte and here it follow the law of mass action
you may consult the following referances:
1.Vogel quantitative analytical chemistry,Longman Publishars.
2-Alexyev quantitative analytical chemistry,Mir Publishars.

[constant thinker]

I don't think there is a definintion. Like samuel_shafek said they are only relative terms. "Diluted" is when you have a relatively low percentage (consentration) of a solute and "concentrated" is when you have a relatively high percentage (concentration) of your solute.

Saturated means that something is holding as much of a solute (or really anything) as possible. Unsaturated fats have some double bonds between the C. Saturated fats have no double bonds between the carbons. There are as many H as possible.

[mike]

Dilute (as a verb) would mean to a chemist that they had to lower the concentration.

Dilute (as an adjective) would mean to a chemist something different for every chemical.

For example: Dilute (v) hydrochloric acid by 10 times = a chemist would have to dilute the HCl so it is ten times less concentrated.

...using dilute (adj) hydrochloric acid.... I would want to be told the concentration (but I guess you wouldn't use conc. HCl (33%?).

The same goes for concentration. Although concentration can be defined as the amount of a compound in a given volume (mol.L-1, g.mL-1 etc) although I guess this could just as easily be referred to as dilution

[GCT]

Just out of curiosity: Is there any definition for "diluited" and "concentrated"

I don't think so, in our lab we use 2M solutions as diluited solutions and satured solutions (e.g. satured HCl-solution) as concentrated.

probably refers to the activity, in pertinence to solvent/analyte relations.  You wouldn't want to use concentration sulfuric acid in titrations, but rather a dilute, perhaps around .1M.

[mike]

probably refers to the activity, in pertinence to solvent/analyte relations.  You wouldn't want to use concentration sulfuric acid in titrations, but rather a dilute, perhaps around .1M.

If somebody told you to use dilute acid though there isn't really a standard concentration refered to as dilute, is there? These are surely relative terms.

[GCT]

If somebody told you to use dilute acid though there isn't really a standard concentration refered to as dilute, is there? These are surely relative terms.

I suppose, but consider the possibility on the significance attached to the two terms.  The times I came across the terms dilute and concentrated it seems that it was directly connected to the method at hand, for instance, for titrations, use dilute NaOH.... concentrated sulfuric acid for where aqueous rate dynamics aren't important.  The concentrated usually meant diminished activity, dilute usually pertained to optimal rate dynamics.  

[Borek]

The concentrated usually meant diminished activity

??

Activity goes down with concentration at first, but later it grows. IIRC 2M CaCl₂ has the same activity coefficients as at 0M concentration, then activity coefficients are getting higher then 1.

[GCT]

??

Activity goes down with concentration at first, but later it grows. IIRC 2M CaCl₂ has the same activity coefficients as at 0M concentration, then activity coefficients are getting higher then 1.

Please refer to the context of the question, the question pertains to the activity in water, as an aqueous analyte.  The >1 activity from the debye huckel equation represents the fact that the solution begins to represent two phases, that is the anayte begins to take on part of the solvent property; the anayte is now "concentrated" it's activity as a solvent approaches + unity.  The activity I'm mentioned is pertinent to the activity in perspective of ideality inw water.