need chemistry help please

Question

Round sig figs correctly

How many grams of oxygen are required for 100.0 grams of citric acid (C6H8O7) to combust completely?

Answer 1

C₆H₈O₇ + 4.5 O₂ ==> 6 CO₂ + 4 H₂O ... balanced equation for combustion of C₆H₈O₇

100.0 g C₆H₈O₇ x 1 mol C₆H₈O₇ / 192.123 g x 4.5 mol O₂ / mol C₆H₈O₇ x 31.9989 g O₂/mol O₂ = 74.95 g O₂