Final answer:
To balance the chemical equation CO + 2H2 yields CH4 + OH and determine the number of moles of each reactant, we need 1 mole of CO and 2 moles of H2.
Step-by-step explanation:
Based on the chemical equation CO + 2H2 yields CH4 + OH, we can determine the number of moles of each reactant needed. The coefficients in front of each substance indicate the stoichiometric ratio, which tells us the ratio of moles of each substance in the reaction. In this case, we need 1 mole of CO and 2 moles of H2 to produce 1 mole of CH4 and 1 mole of OH. Therefore, 1 mole of CO and 2 moles of H2 are needed.