Using the significant figure it would be 27.3
Well, first we must remember that

This is because


So then

The balanced chemical equation is:
2H2 + O2 ---> 2H2O
We are given the amount of the product produced from the reaction. This will be the starting point for the calculations.
355 g H2O ( 1 mol H2O/ 18.02 g H2O) ( 1 mol O2 / 2 mol H2O ) ( 32 g O2 / 1 mol O2 ) = 315.205 g O2
Because if you start at one for example you starting at a extra cm/m/mm. So when you get your measurement result it will be wrong by just one cm/m/mm. Hope this wasn't too confusing.
Precipitation
100°C
When 1 mol of water vapor at 100°C condenses to liquid water at 100°C, 40.7 kJ of heat are released into the surroundings.