Page 290 - Theory and Problems of BEGINNING CHEMISTRY

CHAP. 18] ORGANIC CHEMISTRY 279

18.52. Burning of which compound, CH 3 CH 2 OH or CH 3 CH 3 , is apt to provide more heat? Explain why you made your
choice.
Ans. CH 3 CH 3 . The CH 3 CH 2 OH is already partially oxidized.

18.53. Calculate the concentration of hydroxide ion in 1.00 L of a solution containing 0.100 mol of CH 3 CH 2 NH 2 (K b =
1.6 × 10 −11 ).
−→
+
Ans. RNH 2 + H 2 O ←− RNH 3 + OH −
−
Let x = [OH ].
x 2 −11
= 1.6 × 10
0.100
x = 1.3 × 10 −6 = [OH ]
−
18.54. What functional group is most likely to be found in a polyester shirt?
Ans. Ester C O
O

18.55. The formation of which of the functional groups described in this chapter results in the simultaneous formation of
water?
Ans. Ether, ester, and amide

18.56. Ethyl acetate is reduced by hydrogen in the presence of a catalyst to yield one oxygen-containing organic compound,
but propyl acetate yields two. What are the two compounds?
Ans. CH 3 CH 2 OH and CH 3 CH 2 CH 2 OH
18.57. In this question consider organic molecules with no rings or carbon-to-carbon double or triple bonds. (a) Show that
ethers can be isomers of alcohols but not of aldehydes. (b) Show that aldehydes and ketones can be isomers of each
other, but not of acids or alcohols. (c) Write the condensed formula for all alcohols isomeric with diethyl ether.
Ans. (a) These alcohols have molecular formulas C n H 2n+2 O. Ethers can be thought of as C n H 2n+1 OC n H 2n +1

or C n+n H 2(n+n )+2 O. If n + n = n , the general formula of the ether would be C n H 2n +2 O. Since the

n in the general formula of the alcohol and the n in the general formula of the ether are arbitrary, they
could be the same. The ether can be an isomer of an alcohol.
(b) Both correspond to C n H 2n O
(c) CH 3 CH 2 CH 2 CH 2 OH CH 3 CH 2 CH CH 3
OH
OH

CH 3 CH CH 2 OH CH 3 C CH 3
CH 3 CH 3