Question: how many liters of hydrogen gas are needed to react with cs2 to produce 2.50 l of ch4?
Answer: At STP, one mol of ideal gas occupies 22.4 L. Thus, the balanced equation can be read as 89.6 L of hydrogen gas are needed to produce 22.4 L of methane. If only 2.5 L of methane are needed: 2.50 L CH4 x (89.6 L of H2/22.4 L of CH4) = 10.0 L of H2.