Question: how many grams of oxygen are required to burn 13.0g of c2h2?
Answer: Practically any amount as acetylene gas has a wide range of combustions. However, to burn cleanly, acetylenes formula of c2h2 would weigh 12g/mol carbon 1g/mol hydrogen so (2x12)+(2×1)=26g/2=13g c2h2 so 1/2 mol acetylene to burn most efficiently resulting in co2+h2o would need 3 mol o2. Oxygen is 16g/mol ATOMIC mass.