Question

In the combustion of hydrogen gas, hydrogen reacts with oxygen from the air to form water vapor.
Hydrogen+Oxygen->Water
If you burn 39.7 g of hydrogen and produce 355g of water, how much oxygen reacted?

Answer 1

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