How many grams of oxygen are required to produce 43.0 g of water vapor

Question

How many grams of oxygen are required to produce 43.0 g of water vapor. Please help due tonight! cant seem to figure this equation out!

Answer 1

First, write the correctly balanced equation:

2H₂(g) + O_2(g) ==> 2H₂O(g)

Work in moles. Moles of H₂O to be formed = 43.0 g H₂O x 1 mol/18 g = 2.39 moles H₂O

According to the balanced equation, calculate moles of O₂ needed:

2.39 moles H₂O x 1 mole O₂/2 moles H2O = 1.19 moles O₂ required

Convert this to grams of O₂: 1.19 moles O₂ x 32 g/mole = 38.2 g (to 3 sig. figs.)