Question 31204
from memory, what you have here is:

2 moles of water --> 2 moles of hydrogen + 1 mole of Oxygen


As you have no masses, we cannot use the formula {{{ moles = (mass)/(molecular mass) }}}


So i think it is purely down to the numbers:


2H20 --> 4H and 2O
2H2 --> 4H
O2 --> 2O


all the hydrogen in the water has gone to the hydrogen gas, so if we startetd with 2 moles of hydrogen, we had to finish with 2 moles of hydrogen. I think, from memory and common sense :-)


jon.