posted by jeff .
In the explosion of a hydrogen-filled balloon, 0.54 g of hydrogen reacted with 6.6 g of oxygen to form how many grams of water vapor?
Figure the moles of each.
.54/2=.27 moles H2
Balance the reaction:
well, you need twice as much H2 as O2, so H2 is the limiting reactant. Use the limiting reactant.
figure the mass of .27 moles water