Question

A stream is primarily air (29 g/mole) with a small but measurable amount of methane (16 g/mole). the average molecular weight is: less than 16 more than 16 but less than 29 greater than 29 not enough information

Answer 1

If we have two numbers a & b, then the average must be in between a & b a < a + b/2 < b {if b is larger & a is smaller} Molecular weight of steam = 29 g/mol Molecular weight of Methane = 16 g/mol Average = 29 + 16/2 and this must be 16 < 29 + 16/2 < 29 16 < 22.5 < 29 Hence option b) is correct, i.e more than 16 and less than 29