[windscar]

I would like to identify a white powdery substance (nothing to do with drugs). I think I can ask someone with access to labs on my college; but is it possible? How?

[explosci]

When identifying an unknown there are a few ways to go about it.  For example sometimes a simple IR spectrum can be matched by computer against a database of spectra.  GCMS is also useful here.

If the compound is known and organic the NMR (1H and 13C ) spectra can be compared against spectra in databases like SDBS.

It all depends on what type of compound you think it is.

[Sadi Carnot]

As explosci said, IR and NMR would be extremely helpful (provided you know how to interpret them).  Just keep in mind for those instruments, it is important that the substance is relatively pure.  If you've got a significant amount of some contaminant in the compound it will be very difficult to interpret the spectrum.

There are a number of less precise methods to get you pointed in the right direction.  Find its melting point and compare that to the chemical literature to get a few concrete ideas of what the compound might be.  Test its solubility in different solvents to determine things like whether or not it has polar functional groups.  The list goes on and on.

[fledarmus]

When identifying an unknown there are a few ways to go about it.  For example sometimes a simple IR spectrum can be matched by computer against a database of spectra.  GCMS is also useful here.

If the compound is known and organic the NMR (1H and 13C ) spectra can be compared against spectra in databases like SDBS.

It all depends on what type of compound you think it is.

This is also assuming that it is an organic compound. If it is inorganic, there will probably be neither 1H or 13C specra, and the IR might be useless. Instead, you could use AA or AE spectra to identify the elements involved, and go from there. If the compound is volatile, mass spec could be useful for either organic or inorganic compounds, but many inorganic powders are non-volatile.

There are both traditional wet chemistry and instrumental methods for identifying both inorganic and organic compounds. Many analytical texts have some sort of flowchart in the back that describes how to go through the process of identifying an unknown compound.