2.0 grams of acetylene (C2H2) are required to produce 1.0 moles of CO2. This is because the balanced equation states that for every 2 moles of acetylene (C2H2) that react, 4 moles of CO2 are produced. Therefore, 1.0 moles of CO2 requires 2.0 moles of acetylene (C2H2). Since 1 mole of any substance is equal to its molecular weight in grams, 2.0 grams of acetylene (C2H2) are required to produce 1.0 moles of CO2 making the answer 10.0 grams.