...
At this point, you have measured
or can easily calculate
the following

A. Mass of UNKNOWN used
B. Mass of GAS generated
C. Mass of WATER displaced by gas
D.
Pressure of Gas collected
E. Temperature of gas 
A
and B are used to
determine the % KClO_{3} in the UNKNOWN
The relationship of mass of gas generated to mass of KClO_{3} present is
given by
2 KClO_{3} > 2 KCl + 3 O_{2}
B, C, D
and E are used to
calculate the Molar Volume at STP
C is converted to
Volume using the density of water
D must be corrected
for the vapor pressure of
water
E and the corrected D are used to convert the Volume calculated
from C to Volume at
STP
