A brass alloy contains 71.1 % copper, Cu, by mass with the remainder of the alloy being zinc, Zn. Determine the number of moles of zinc in 44.7 g of the brass alloy.

)in the deacon process for the manufacture of chlorine, hcl and o2 react to form cl2 and h2o. sufficient air (21 mole% o2, 79% n2) is fed to provide 35% excess oxygen, and the fractional conversion of hcl is 85%. calculate the mole fractions of the product stream components.