Conserving Research Chemicals

[Rush]

Do research chems have a degradation in time?


i mean, if they are far from light, in a close place(not in open air,standard powder packets)...they should be good for a lot of years, or they'll degrade in rapid times?

and liquid form(in alchool, cos most RC are not soluble in water) is better or worst than powder(solid) ??

and room temperature is ok??(20° celsius)
or its better to keep in fridge or in freezer??
there are some cathegories which are more suceptible to this problem?(between trypts,phens, piperazines, and other ones)

thank you very much!!!