Can someone please answer this for me.

Question

Given the following equation:

2 C₄H₁₀ + 13 O₂ → 8 CO₂ + 10 H₂O

How many moles of O₂ are needed to produce 2.81 mol of H₂O?

________mol O₂

Answer 1

The ratio of mol O₂ to mol H₂O is 13/10

2.81 mol H₂O x 13 mol O₂/ 10 mol H₂O = 3.65 mol O₂ needed