Consider the reaction CH4(g) + 2O2(g)—> CO2(g)+2H2O(g) how many grams of methane should be burned in an excess of oxygen at STP to obtain 5.6 L of carbon dioxide?
2.0 g
4.0 g
16.0 g
32.0 g

Explanation:

CH₄(g) + 2O₂(g)—> CO₂(g)+2H₂O(g)

                                22.4 L

22.4 litre of CO₂ is formed by 1 mol of methane

5.6 litre of CO₂ will be formed by 5.6 / 224. mol of methane

= mole of methane required = .25 mol of methane

= .25 x 16 = 4 gram of methane  ( mol weight of methane = 16 gm )

it's all four options.