The stoichiometric relationship for methane (CH4) combustion, as represented by the balanced chemical equation: \[ CH_4 + 2 O_2 \rightarrow CO_2 + 2 H_2O \] indicates that one mole of methane reacts with two moles of oxygen. Consequently, 0.25 moles of methane necessitate: \[ 0.25 \, \text{mol CH}_4 \times 2 \, \text{mol O}_2/\text{mol CH}_4 = 0.5 \, \text{mol O}_2 \] At standard temperature and pressure (S.T.P.), one mole of any gas occupies 22.4 L. Therefore, the calculated volume of oxygen required is: \[ 0.5 \, \text{mol O}_2 \times 22.4 \, \text{L/mol} = 11.2 \, \text{L} \]