## Chemistry and Chemical Reactivity (9th Edition)

a) Bonds broken: 2 N-H, 2 C-O Bonds formed: 2 N-C, 2 O-H From bond dissociation enthalpy: $2×391+2×358-2×305-2×463=-38\ kJ/mol$ Exothermic b) $1\ OC(NH_2)_2+1\ CH_2(COOH)_2\rightarrow 2\ H_2O+1\ C_4H_4O_3N_2$ c,d ) The nitrogens and the carbon bonded to two hydrogens are $sp^3$ hybridized, and have bond angles of approximately 109°, the other carbons are double bonded to oxygens so they are $sp^2$ hybridized and their bond angles are approximately 120°. e) The C=O bonds are the most polar, according to figure 8.10, because they have the greatest difference in electronegativity. f) Yes, dipoles from the NH bonds won't cancel each other out in the vectorial sum, unlike those from the C=O ones.