Question

In the combustion of hydrogen gas, hydrogen reacts with oxygen from the air to form water vapor. If you burn 36.9 g of hydrogen and produce 3.30 × 102 g of water, how much oxygen reacted?

Answer 1

that's 10^2 g, sorry, it didn't paste correctly

Answer 2

use the grams of water to calculate how many moles there are (giving an indication of how many particles of water formed)

using this we can deduce how many oxygen atoms we would need to make said amount of water.

if oxygen comes in pairs we can figure out how many oxygen molecules we need, ergo how many moles we need.

lastly knowing that a mole of oxygen weights 32 g, we can calculate how many grams of oxygen must have reacted to provide enough O atoms to create said amount of water