Can someone please solve 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 2.51 mol of H2O?

Answer 1

We are given the balanced chemical equation: 2C₄H₁₀ + 13 O₂ → 8 CO₂ + 10 H₂O. And we are asked to find how many moles of O₂ are needed to produce 2.51 moles of H₂O. This means that the units that we want to end up with are moles of O₂.

Since we are given 2.51 moles of H₂O in the question, this is what we start our equation with:

2.51 mol H₂O

Now, we want to see how we can relate moles of H₂O with moles of O₂. Looking at the given chemical equation, 2C₄H₁₀ + 13 O₂ → 8 CO₂ + 10 H₂O, we can see that there are 13 mol O₂ for every 10 mol H₂O. We found this out by looking at the coefficents (in bold) in the chemical equations. Now, using stoichiometry, we can use the mole ratios of O₂ and H₂O to cancel out the moles of H₂O and leave us with moles of O₂. To clarify, the mole ratio of O₂ and H₂O is 13 mol O₂ / 10 mol H₂O.

2.51 mol H₂O x (13 mol O₂ / 10 mol H₂O)

2.51 mol H₂O x (13 mol O₂ / 10 mol H₂O) = 3.263 mol O₂ = 3.26 mol O₂ (3 significant figures)