MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Transcription

1 CHE Fall Chapter 8 Homework 8 (Chapter 8: Basic concepts of chemical bonding) MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Of the possible bonds between carbon atoms (single, double, and triple),. A) a single bond is stronger than a double bond B)a double bond is longer than a triple bond C) a double bond is stronger than a triple bond D) a single bond is stronger than a triple bond E)a triple bond is longer than a single bond 2)In the Lewis symbol for a sulfur atom, there are paired and unpaired electrons. A) 4, 2 B)2, 2 C) 0, 6 D)5, 1 E)2, 4 3) Which atom can accommodate an octet of electrons, but doesn't necessarily have to accommodate an octet? A) O B)N C) B D)C E)H 4) Which of the following does not have eight valence electrons? A) Rb+1 B) Xe C) Ti+4 D) Cl- E) Sr+1 5)Given that the average bond energies for C-H and C-Br bonds are 413 and 276 kj/mol, respectively, the heat of atomization of bromoform (CHBr 3 ) is kj/mol. A) 1241 B)-1378 C) -689 D) 1378 E) 689 6)Resonance structures differ by. A) placement of atoms only B) placement of electrons only C) number of atoms only D) number and placement of electrons E) number of electrons only 1) 2) 3) 4) 5) 6) 1

2 7)Using the Born-Haber cycle, the ΔHf of KBr is equal to. A) ΔHf [K (g)] + ΔH f [Br (g)] + I 1 (K) + E(Br) - ΔH lattice B)ΔHf [K (g)] - ΔHf [Br (g)] - I1(K) - E(Br) - ΔHlattice C) ΔHf [K (g)] + ΔHf [Br (g)] - I1 - E(Br) + ΔHlattice D) ΔH f [K (g)] + ΔH f [Br (g)] + I 1 (K) + E(Br) + ΔH lattice E)ΔH f [K (g)] - ΔH f [Br (g)] + I 1 (K) - E(Br) + ΔH lattice 8)In the nitrite ion (NO2 - ),. A) there are 20 valence electrons B)both bonds are the same C) both bonds are double bonds D) one bond is a double bond and the other is a single bond E)both bonds are single bonds 9)Based on the octet rule, boron will most likely form a ion. A) B2+ B)B2- C) B1+ D)B3+ E)B3-10)The type of compound that is most likely to contain a covalent bond is. A) held together by the electrostatic forces between oppositely charged ions B)a solid metal C) one that is composed of only nonmetals D) one that is composed of a metal from the far left of the periodic table and a nonmetal from the far right of the periodic table E)There is no general rule to predict covalency in bonds. 11)Of the atoms below, is the least electronegative. A) F B)Si C) Rb D)Ca E)Cl 12) As the number of covalent bonds between two atoms increases, the distance between the atoms and the strength of the bond between them. A) increases, increases B) decreases, decreases C) increases, decreases D) decreases, increases E) is unpredictable 7) 8) 9) 10) 11) 12) 2

3 13)Bond enthalpy is. A) always positive B) always negative C) sometimes positive, sometimes negative D) always zero E) unpredictable 14)Of the molecules below, the bond in is the most polar. A) HI B)HF C) HBr D)H2 E)HCl 13) 14) 15) The chloride of which of the following metals should have the greatest lattice energy? A) lithium B) rubidium C) potassium D) sodium E) cesium 16)Which of the following names is/are correct for the compound TiO 2? A) titanium dioxide and titanium (IV) oxide B) titanium oxide C) titanium (IV) dioxide D) titanium oxide and titanium (IV) dioxide E) titanium (II) oxide 15) 16) 17) Of the ions below, only has a noble gas electron configuration. A) I + B)S 3- C) K - D)O 2+ E)Cl - 17) 18) A valid Lewis structure of cannot be drawn without violating the A) CO 2 B)CCl 4 C) PCl 3 D)ClF 3 E)SO 3 18) 19)Dynamite consists of nitroglycerine mixed with. A) damp KOH B) solid carbon C) TNT D) potassium nitrate E) diatomaceous earth or cellulose 19) 3

4 20)The Lewis structure of N2 H 2 shows. A) each nitrogen has one nonbonding electron pair B) each nitrogen has two nonbonding electron pairs C) a nitrogen-nitrogen single bond D) a nitrogen-nitrogen triple bond E) each hydrogen has one nonbonding electron pair 21) Most explosives are compounds that decompose rapidly to produce products and a great deal of. A) gaseous, gases B) solid, gas C) liquid, heat D) soluble, heat E) gaseous, heat 22)For resonance forms of a molecule or ion,. A) the observed structure is an average of the resonance forms B) there cannot be more than two resonance structures for a given species C) one always corresponds to the observed structure D) the same atoms need not be bonded to each other in all resonance forms E) all the resonance structures are observed in various proportions 23)Which of the following names is/are correct for the compound SnCl 4? A) tin (IV) tetrachloride B) tin chloride C) tin chloride and tin (II) tetrachloride D) tin tetrachloride and tin (IV) chloride E)tin (II) chloride and tin (IV) chloride 24) A valid Lewis structure of cannot be drawn without violating the A) ICl 5 B)NI 3 C) SO 2 D)SiF 4 E)CO 2 20) 21) 22) 23) 24) 25) Of the following, cannot accommodate more than an octet of electrons. A) P B)O C) As D)I E)S 25) 26) The electron configuration [Kr]4d10 represents. A) Te+2 B) Sn+2 C) Ag+1 D) Rb+1 E) Sr+2 26) 27) The central atom in does not violate the A) CF 4 B)KrF 2 C) XeF 4 D)ICl 4 - E)SF 4 27) 4

5 28)Of the bonds below, is the least polar. A) C, F B)Si, Cl C) Na, Cl D)Na, S E)P, S 28) For the questions that follow, consider the BEST Lewis structures of the following oxyanions: (i)no2 - (ii)no3 - (iii) SO3 2- (iv)so4 2- (v) BrO3-29)In which of the ions do all X-O bonds (X indicates the central atom) have the same length? A) none B)all C) (i) and (ii) D) (iii) and (v) E)(iii), (iv), and (v) 30) There can be four equivalent best resonance structures of. A) (i) B)(ii) C) (iii) D)(iv) E)(v) 31) Which of the following has eight valence electrons? A) Ti 4+ B)Na + C) Cl - D) Kr E)all of the above 32)The Lewis structure of the CO3 2- ion is. A) 29) 30) 31) 32) B) 5

6 C) D) E) 33)The oxidation number of phosphorus in PF3 is. A) +1 B)+2 C) +3 D) -2 E)-3 34)Of the atoms below, is the most electronegative. A) F B)N C) Br D)Cl E)O 35) A valid Lewis structure of cannot be drawn without violating the A) SO2 B)SO3 2- C) NF3 D)CF4 E)BeH2 36) Which of the following has the bonds correctly arranged in order of increasing polarity? A) O F, Be F, Mg F, N F B)Mg F, Be F, N F, O F C) O F, N F, Be F, Mg F D) Be F, Mg F, N F, O F E)N F, Be F, Mg F, O F 33) 34) 35) 36) 6

7 37)Why don't we draw double bonds between the Be atom and the Cl atoms in BeCl2? A) That would result in more than eight electrons around each chlorine atom. B)That would result in the formal charges not adding up to zero. C) That would give positive formal charges to the chlorine atoms and a negative formal charge to the beryllium atom. D) There aren't enough electrons. E) That would result in more than eight electrons around beryllium. 38) A valid Lewis structure of cannot be drawn without violating the A) SeF4 B)SiF4 C) CF4 D)PO4 3- E)NF3 37) 38) 39) Which two bonds are most similar in polarity? A) B F and Cl F B)Al Cl and I Br C) I Br and Si Cl D) Cl Cl and Be Cl E)O F and Cl F 40)In ionic bond formation, the lattice energy of ions as the magnitude of the ion charges and the radii. A) increases, increase, increase B) increases, decrease, decrease C) decreases, increase, increase D) increases, increase, decrease E) increases, decrease, increase 39) 40) 7