The grams of oxygen that is required to react completely with 859.0 g C₂H₂ is 2643.2 grams
calculation
Step 1: write the equation for reaction between C₂H₂ and O₂
that is 2C₂H₂ +5O₂ → 4 CO₂ +2H₂O
Step 2 : find the moles of C₂H₂
moles = mass/molar mass
From periodic table the molar mass of C₂H₂ = (12 x2) +( 1 x2) = 26 g/mol
moles= 859.0 g /26 g/mol =33.04 moles
step 3 : use the moles ratio to determine the moles of O₂
C₂H₂:O₂ is 2:5 therefore the moles of O₂ =33.04 x5/2 = 82.6 moles
Step 4: find mass of O2
mass = moles x molar mass
from periodic table the molar mass of O₂ = 16 x2 = 32 g/mol
mass = 82.6 moles x 32 g/mol =2643.2 grams