Why do you think there are 2 hydrogen atoms and only 1 oxygen atom in this compound

Consider the following reaction at equilibrium. 2co2 (g) 2co (g) + o2 (g) h° = -514 kj le châtelier's principle predicts that the equilibrium partial pressure of co (g) can be maximized by carrying out the reaction a. at high temperature and high pressure b. at high temperature and low pressure c. at low temperature and low pressure d. at low temperature and high pressure e. in the presence of solid carbon

Ineed ! i have no clue how to do this problem.

What type of matter is made of only one kind of atom