The acetylene tank contains 35.0 mol C2H2, and the oxygen tank contains 84.0 mol O2. How many moles of O2 are needed to react completely with 35.0 mol C2H2? ___mol O2

The moles of O2 that are needed to react completely with 35.0 mol C2H2 is 87.5 moles of O2

Explanation

Write a balanced chemical equation for reaction of between C2H2 and O2

2 C2H2 + 5O2 → 4 CO2 + 2 H2O

if 35.0 moles C2H2 reacted then use the o mole ratio to determine the moles of C2H2

The mole ratio of C2H2 : O2 = 2:5 therefore the moles of O2

= 35 moles x5/2 = 87.5 moles of O2