What volume of carbon dioxide can be produced from the combustion of 2.0 L of methane at STP?

First, state the balanced equation that represents the combustion:

CH4 + 2O2 → CO2 + 2H2O

Second, state the molar ratios: 1 mol CH4 : 1 mol CO2.

Third, given that at constant temperature and pressure, the volume of an ideal gas is proportinal to the number of moles, you can state the volumetric proportion:

1 Liter of CH4 : 1 Liter of CO2.

Fourth, use the volumetric proportion:

2.0 Liter CH4 * 1 Liter CO2 / 1 Liter CH4 = 2.0 Liter CO2.

Answer: 2.0 Liter CO2.