An organic solid has a vapor pressure of 900 torr at its melting point explain how you would purify this compound

The best method that can be used to purify this compound is SUBLIMATION METHOD. This is because the compound has a high vapor pressure [900 torr] at its melting point. 
If sublimation is used to purify this compound, at its melting point, the solid will sublime and escape in form of vapors leaving the impurities behind. The vapor will then be cooled and the pure solid compound will be obtained.  This method is appropriate in this case because the impurities involved has low vapor pressure.

I’d have to say no because without oxygen in the water the fish would all be dead. so if you want to fish for dead fish, pick the ponds with the lowest oxygen concentrations.

The answer is 5 10 15