A11.7-g sample of methane (ch4) reacts with 46.7 g of oxygen gas in a container fitted with a piston (at 1.00 atm and 436 k). methane can react with oxygen to form carbon dioxide and water vapor or carbon monoxide and water vapor. after the combustion reaction is complete, the gas density at the given conditions is observed to be 0.7215 g/l. calculate the mole fraction of methane that reacts to form carbon monoxide rather than carbon dioxide

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.