A mixture of methane and air is capable of being ignited only if the mole percent of methane is between 5% (lower) and 15% (upper flammability limits). 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 limit.(a)Calculate the required flow rate of air in mol/h.(b)Calculate the percent, by mass, of oxygen in the product gas.(c)Calculate the flow rate of an 47% methane stream that would have to be added to the original stream to prevent the the mixture from igniting.(d)Qualitatively explain why there are upper and lower flammability limits.

i'm assuming that the correct answer is indeed the first one/ "a"..

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.