Consider a sample that is a mixture composed of biphenyl, benzoic acid, and benzyl alcohol. predict the order of elution of the components in this mixture. assume that the chromatography uses a silica column and the solvent system is based on cyclohexane, with an increasing proportion of methylene chloride added as a function of time.

biphenyl, benzyl alcohol, benzoic acid

Explanation:

Due to the nonpolar nature of cyclohexane, biphenyl will be the first solute to be eluted due to the presence of two phenyl rings. The second solute to be eluted will be benzyl alcohol due to the presence of OH group. This is because it has the ability to exhibit hydrogen bond with the silica column of the chromatography. Lastly, the benzoic acid will be the third solute to be eluted due to the presence of COOH group which is more polar than the OH group. Therefore, the order of elution of the components in the mixture is biphenyl, benzyl alcohol, benzoic acid.

n2(g) + 3h2-> 2nh3(g)   this is the balanced equation

note the mole ratio between n2, h2 and nh3.   it is 1 : 3 : 2   this will be important.

moles n2 present = 28.0 g n2 x 1 mole n2/28 g = 1 mole n2 present

moles h2 present = 25.0 g h2 x 1 mole h2/2 g = 12.5 moles h2 present

based on mole ratio, n2 is limiting in this situation because there is more than enough h2 but not enough n2.

moles nh3 that can be produced = 1 mole n2 x 2 moles nh3/mole n2 = 2 moles nh3 can be produced

grams of nh3 that can be produced = 2 moles nh3 x 17 g/mole = 34 grams of nh3 can be produced

note:   the key to this problem is recognizing that n2 is limiting, and therefore limits how much nh3 can be produced.

the answer is a! (2.9 x 10^-18 j) hope i could someone. : )