A mixture of methane and air is capable of being ignited only if the mole percent of methane is between 5% and 15%. A mixture containing 9.0 mole% methane in air flowing at a rate of 7.00 x 10² kg/h is to be diluted with pure air to reduce the methane concentration to the lower flammability limit. Calculate the required flow rate of air in mol/h and the percent mass by mass of oxygen in the product gas. (Note: Air may be taken to consist of 21 mole% O₂ and 79% N₂ and to have an average molecular weight of 29.0)