Need help with Chem

Question

If 100.0 molecules of H₂ and 43.0 molecules of O₂ react, how many molecules of H₂O can be produced in the reaction below?

2 H₂(g) + O₂( g) —> 2 H₂O(g)

Answer 1

2 H₂(g) + O₂( g) —> 2 H₂O(g) ... balanced equation

100..........43...................?..........molecules

Which reactant (H₂ or O₂) is in limiting supply? It would be the O₂ because it takes twice as much H₂ as O₂ and there is at least twice as much H₂ as O₂ (you'd only need 86 molecules of H₂). The limiting reactant will determine the amount of product (H₂O) that can be made.

Use dimensional analysis using the coefficients in the balanced equation:

43 molecules O₂ x 2 molecules H₂O / molecule of O₂ = 86 molecules of H₂O