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NH_2(CH_2)_5NH_2 (b.p. 179), butane-1, 4-diol (b.p. 235) a. easier to rotate in

ID: 500310 • Letter: N

Question

NH_2(CH_2)_5NH_2 (b.p. 179), butane-1, 4-diol (b.p. 235) a. easier to rotate in place 2, 2-dimethylpropane-1, 3-diol (b.p. 208), pentane-1, 5-diol (b.p. 242) b. greater weight butan-1-ol (b.p. 118), CH_3(CH_2)_3 I (b.p. 131) c. more hydrogen bonds pentane-1, 5-diol (m.p. -18), 2, 2-dimethylpropane-1, 3-diol (m.p. 129) d. more polar bonds pentane-1, 5-diol (m.p.-18), NH_2 (CH_2)_5 NH_2 (m.p.12) e. more van der Wall interactions Using the method that we learned in class to estimate specific gravities and given the following atomic weights (C = 12, H = 1, N = 14, O = 16), which compound has a density closest to that of water? Compound 6. e. will? a. sink in water b. make an emulsion with water c. float on water d. dissolve in water e. not a.-d To the nearest tenth, what is the pH of a 1.0 M solution of trifluoroacetic acid (CF_3CO_2H) with a pK_a 0.2? a. 0.9 b. 0.7 c. 0.5 d. 0.3 e. not a.-d. Given that for aspirin pK_ow = -1.2, starting with 1 gram (two extra-strength tablets) of aspiring in 8 ounces (a cup) water, to the nearest tenth of a gram, how much aspiring is extracted into a tablespoon (1/2 an ounce) of octan-1

Explanation / Answer

6. Water is polar, so a more polar compound among the list would have similar density like water,

c.

would have similar density

7. Compound 6e being organic and more hydrophobic in nature would not mix with aqueous layer and thus would,

c. float on water

8. pH of 1.0 M trifloroacetic acid,

pKa = -log[Ka]

Ka = 0.631

with x amount of acid dissociated

0.631 = x^2/(1 - x)

x^2 + 0.631x - 0.631 = 0

x = [H+] = 0.54 M

pH = -log[H+] = 0.3

Answrr : d. 0.3