Question

1. refer to figure 4.5 (above) - which of the structure(s) contain a carboxyl functional group? a) a b) b c) c d) c and e e) none of the structures 11) what results from an unequal sharing of electrons between atoms? a) a nonpolar covalent bond b) a polar covalent bond c) an ionic bond d) a hydrophobic interaction e) a hydrogen bond 12) what is the maximum number of covalent bonds that an oxygen atom with atomic number 8 can make? a) 4 b) 6 c) 1 d) 2 e) 8 13) which functional group is not present in this molecule? ho c o h h - c - c - oh h n h h a) sulfhydryl b) amino c) carboxyl d) hydroxyl e) all are present 14) the kind and number of bonds an atom can form depends on _. a) its atomic number b) its atomic mass c) the number of particles in its nucleus d) its outer (valance) electron configuration 15) which of the following results from a transfer of electron(s) between atoms? a) hydrogen bond b) nonpolar covalent bond c) hydrophobic interaction d) ionic bond e) polar covalent bond 16) measurements show that the ph of a particular lake is 4.0. what is the proton concentration, h+, of the lake? a) 10 - 10 b) - 4.0 c) 4.0 d) 10 - 4 17) what is the ph of a solution with a hydroxide ion, oh - , concentration of 10 - 12 m? a) ph 12 b) ph 14 c) ph 10 d) ph 4 e) ph 2

Explanation:

Step1: Recall bond - type definitions

Unequal sharing of electrons between atoms results in a polar covalent bond. A non - polar covalent bond has equal sharing, an ionic bond is from electron transfer, and hydrogen and hydrophobic interactions are not from electron - sharing in the same sense as covalent bonds. So for question 11, the answer is B.

Step2: Analyze oxygen's valence electrons

Oxygen has 6 valence electrons. It can share 2 electrons to complete its octet, so it can form a maximum of 2 covalent bonds. For question 12, the answer is D.

Step3: Identify functional groups in the molecule

The given molecule has an amino group ($-NH_2$), a carboxyl group ($-COOH$) and hydroxyl groups ($-OH$), but no sulfhydryl group ($-SH$). For question 13, the answer is A.

Step4: Understand bonding determinants

The kind and number of bonds an atom can form depends on its outer (valence) electron configuration. For question 14, the answer is D.

Step5: Recall bond - formation mechanisms

An ionic bond results from a transfer of electrons between atoms. For question 15, the answer is D.

Step6: Use pH formula

The pH is defined as $pH = -\log[H^+]$. If $pH = 4.0$, then $[H^+]=10^{-4}$. For question 16, the answer is D.

Step7: Calculate pH from $[OH^-]$

First, use the relationship $[H^+][OH^-]=10^{-14}$. Given $[OH^-]=10^{-12}$, then $[H^+]=\frac{10^{-14}}{10^{-12}} = 10^{-2}$. And $pH=-\log[H^+]=2$. For question 17, the answer is E.

Answer:

1. B. a polar covalent bond
2. D. 2
3. A. sulfhydryl
4. D. its outer (valence) electron configuration
5. D. ionic bond
6. D. $10^{-4}$
7. E. pH 2