Question

Calculate the volume of o2 at stp required to form 1 kg of methane

Answer 1

The balanced chemical equation for combustion of methane is given as:
​CH4  +  2O2  →  CO2  +  2H2O 
So 1 mole of CH4 requires 2 moles of O2 for complete combustion.
Molar mass of methane = 16 g.
Number of moles of methane in 4 g sample = 4 g/16 g = 1/4 mole.
If ​1 mole of CH4 requires 2 moles of O2 for complete combustion.
Therefore 1/4 ​mole of CH4 will requires = 1/4 ×2 moles of O2 = 0.5 mol of O2 for complete combustion.
1 mole of all the gases occupy 22.4 L at STP
Therefore 0.5 mole will occpy 22.4 L × 0.5 mol = 11.2 L
So 11.2 L of O2 is required for complete combustion of 4 g CH4.