How many grams of o2 are produced as 0.033 mol of water decompose

 This can be quickly solved with "traintracks"

Explanation:

You start w/ grams of water and want to find moles of oxygen gas produced.  

So you want to Convert:  

Grams of water -> moles of water -> moles of oxygen gas.  

The two things you need to know to set up the tracks are:  

1)Molar mass of water- H2O  

Hydrogen - 1.008(x2)  

Oxygen - 16.00  

Water - 18.016

it has both hydrogen and oxygen