Amixture 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 700 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 by mass of oxygen in the product gas. (note: air may be taken to consist of 21 mole% o and 79% n2 and to have an average molecular weight of 29.0.)
(a)n = 20,200 mol air/h; 0.225 kg o2/kg

7. using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. use 3 – 4 sentences in your explanation. 8. when a 2.5 mol of sugar (c12h22o11) are added to a certain amount of water the boiling point is raised by 1 celsius degree. if 2.5 mol of aluminum nitrate is added to the same amount of water, by how much will the boiling point be changed? show all calculations leading to your answer or use 3 – 4 sentences to explain your answer. 9. if 5.40 kcal of heat is added to 1.00 kg of water at 100⁰c, how much steam at 100⁰c is produced? show all calculations leading to an answer. 10. the freezing of water at 0⁰c can be represented as follows: h2o (l) ↔ h2o(s) the density of liquid water is 1.00 g/cm3. the density of ice is 0.92 g/cm3. in 3 – 4 sentences explain why applying pressure causes ice to melt.