Researchers in the Ceyer group at MIT are developing catalysts to convert natural gas directly into methanol. Methanol is currently produced by reacting syngas, a mixture of carbon monoxide and hydrogen gas. Assuming that all methanol produced is in the gas phase, if 4 liters of carbon monoxide gas and 4 liters of hydrogen gas are reacted completely to produce methanol, what is the final volume of the reaction mixture in liters?