In the reaction 2CO(g) + O2 (g) ? 2CO2 (g), what is the ratio of moles of oxygen used to moles of CO2 produced? Chemistry In the reaction 2CO(g) + O2 (g) ? 2CO2 (g), what is the ratio of moles of oxygen used to moles of CO2 produced? a. 1:1 b. 2:1 c. 1:2 d. 2:2 Answer: C Learn More : Share this Share on FacebookTweet on TwitterPlus on Google+