What is the maximum number of moles of carbon dioxide that can be produced by the reaction of 0.90 moles of carbon monoxide with 0.60 moles of oxygen?

0.90molCO2

Explanation:

You create a balanced equation of the two reactants and one product

2CO+O2=2CO2

Then you convert both reactants into moles of the product and the smaller number is the maximum amount of moles of the product you can create. This is because there is only enough of that one product to make the certain amount of moles, the other product will just have some left over.