Question

When 1. 57 mol o2 reacts with h2 to form h2o , how many moles of h2 are consumed in the process?.

Answer 1

Consult the balanced reaction:

O₂ + 2 H₂   ⇄   2 H₂O

which says you need twice as many moles of H₂ as O₂. So if 1.57 mol O₂ is available, then the reaction would consume 2 × 1.57 = 3.14 mol H₂.