Answer:
a) 0.253
Explanation:
2H₂ + O₂ ⟶ 2H₂O
We want to convert moles of H₂O to moles of H₂.
Choose the conversion factor (the correct molar ratio)
It is or either 2 mol H₂/2 mol H₂O or 2 mol H₂O/2mol H₂
We choose the one with the desired units (mol H₂) on top.
Moles of H₂ = 0.253 mol H₂O × 2 mol H₂/2 mol H₂O
Moles of H₂ = 0.253 mol H₂
