find the volume of a dry gas at STP if it measures 806cm3 at 26.3Celsius and103.o kPa when collected over H2O?

Answer 1

If it is collected over water, it is a "wet gas". To correct for this, find the vapor pressure of water at 26.3 C (there are tables for this) divide that by 103 KPa. Now you can use the reduced pressure of (1-division result)*806 cc to find the dry volume.