CHEM LC 2

(LO 24)  Which of the following is/are true?

1. Se has a smaller radius than Se^2–

2. Se has a larger radius than Rb

3. Rb has a larger radius than Rb⁺

4. Rb⁺ has a smaller radius than Se^2–

5. The effective nuclear charge of rubidium is about 1;  the effective nuclear charge of selenium is about 4.

A, C, and D

(LO 25 and LO 26) Which of the following is/are true? The electron configuration for Se2– is [Ar]4s2 3d10 4p6 so it is paramagnetic The electron configuration for Pb4+ is [Xe] 4f14 5d10 so it is diamagnetic Co2+ has 5 unpaired electrons and is paramagnetic Zn2+ is diamagnetic

B and D

(LO 27)  Which of the following is/are true?

1. The first ionization energy of Cs is less than the first ionization energy of Ba.

2. The first ionization energy of Ba is greater than the first ionization energy of Ca.

3. The second ionization energy of Cs is greater than the second ionization energy of Ba.

4. The third ionization energy of Cs is greater than the third ionization energy of Ba.

A and C

LO 28)  Which of the following is/are true?

1. Potassium has more metallic character than iron.

2. Electron affinities are generally negative (exothermic) while ionization energies are positive (endothermic).

3. Na has a more exothermic electron affinity than Cl.

4. Cl has a more exothermic electron affinity than Ar.

5. K has a more exothermic electron affinity than Na.

A, B, and D

LO 29)  Which of the following is/are true?

1. Covalent bonding involves transferring electrons; ionic bonding involves sharing electrons.

2. Chemical bonds form to decrease the potential energy of the charged particles that compose atoms.

3. The empirical formula of C₆H₁₂O₆ is C₂H₄O₂.

4. More than one compound can have the same empirical formula.

5. The molecular formula cannot be the same as the empirical formula for a compound.

6. A covalent compound typically forms between two or more nonmetals; an ionic compound typically forms between a nonmetal and a metal.

B, D, and F

(LO 30)  Which of the following is/are true?

1. The ionic compound formed from I and Sr is Sr₂I.

2. The charge of Sn in SnO₂ is 4+.

3. The ionic compound formed from Ba and Se is Ba₂Se₂.

4. The charge of Mn in Mn₂O₃ is 3+.

B and D

(LO 31)  Which of the following is/are correct for both formula and name?

1. Ni₂O₃ is nickel(III) oxide

2. ZnBr₂ is zinc bromide

3. Ag₂S is silver(I) sulfide

4. CaF₃ is calcium fluoride

5. Na₃N is sodium nitrite

A and B

(LO 32)  Which of the following is/are correct for both formula and name?

1. Mg(NO₃)₂ • 6H₂O is magnesium nitrite hexahydrate

2. Fe(C₂H₃O₂)₂ • 4H₂O is iron(II) acetate tetrahydrate

3. CaHPO₄ is calcium hydrogen phosphate

4. BaBrO₂ is barium hypobromite

5. Fe₂(CrO₄)₃ is iron(III) dichromate.

6. Sr₃N₂ is strontium nitride

B, C, and F

What is the formal charge of the oxygen atom in this Lewis structure for N₂O?

1

(LO 41)  What is the formal charge of the oxygen atom in this Lewis structure of N₂O?

-1

(LO 41)  What is the formal charge of the oxygen atom for this Lewis structure of N₂O?

0

(LO 41)  Assign formal charges to the remaining atoms in each resonance structure of N₂O.  Which resonance structure (1, 2, or 3) is most favorable?

 

2

(LO 42)  Draw the best resonance structure(s) for the bromate anion.  Which of the following is/are true?  Select all that apply.

1. There are three equally good resonance structures

2. In a best resonance structure, there are three single bonds

3. In a best resonance structure, there is a 0 formal charge on two oxygen atoms and a -1 formal charge on one oxygen atom

4. In a best resonance structure, there is a 0 formal charge on the bromine atom

5. In a best resonance structure, there are no lone pairs of electrons on bromine

a,c,d

LO 43)  Draw the best Lewis structure for C₂H₄, C₂H₂, and C₂H₆; also consider the resonance structures for C₆H₆ (benzene, a 6-membered carbon ring shown below).  Which of the following is/are true? Select all that apply.

1. The bond between the two carbon atoms in C₂H₂ is shorter than the bond between the two carbon atoms in C₂H₄

2. The bond between the two carbon atoms in C₂H₆ is stronger than the bond between the two carbon atoms in C₂H₂

3. The bond between any two carbon atoms in C₆H₆ is longer than the bond between the two carbon atoms in C₂H₄

4. The bond between any two carbon atoms in C₆H₆ is weaker than the bond between the two carbon atoms in C₂H₆

Answer

a,c

(LO 44)  Which of the following is/are true?

1. In VSEPR Theory, electron groups are generally positioned as far away from each other as geometry allows according to the number of electron groups on the atom

2. In VSEPR Theory, a lone pair of electrons counts as one electron group

3. In VSEPR Theory, a triple bond counts as three electron groups

4. In VSEPR Theory, a single bond takes up slightly more space around an atom than a lone pair of electrons.

5. If there are 3 bonding groups and 2 lone pairs, the molecular geometry will be T-shape

6. If there are 2 bonding groups and 2 lone pairs, the molecular geometry will be linear

Answer

A, B, and E

(LO 24)  Which of the following is/are true?  Select all that apply.

1. Ca has a smaller radius than Ca²⁺

2. S has a smaller radius than Ca

3. S^2– has a smaller radius than Ca²⁺ 

4. The effective nuclear charge of Ca is about 2;  the effective nuclear charge of S is about 6

Answer

B and D

(LO 27)  Which of the following is/are true?  Select all that apply.

1. The first ionization energy of Ba is greater than the first ionization energy of Ca.

2. The first ionization energy of K is less than the first ionization energy of Ca.

3. The second ionization energy of K is greater than the second ionization energy of Ca.

4. The third ionization energy of K is greater than the third ionization energy of Ca.

Answer

B and C

(LO 28)  Which of the following is/are true?  Select all that apply.

1. Calcium has more metallic character than nickel

2. K has a more exothermic electron affinity than Cs.

3. K has a more exothermic electron affinity than Br.

4. Kr has a more exothermic electron affinity than Br.

Answer

A and B

(LO 29, LO 30, and LO 33)  Which of the following is/are true?  Select all that apply.

1. Covalent bonding involves transferring electrons; ionic bonding involves sharing electrons.

2. Chemical bonds form to decrease the potential energy of the charged particles that compose atoms.

3. A covalent compound typically forms between two or more nonmetals; an ionic compound typically forms between a nonmetal and a metal.

4. The compound formed between Ca and Br has the formula Ca₂Br

5. In Mn₂O₃, Mn has a 2+ charge

6. A double bond involves two adjacent atoms sharing 4 electrons

B, C, and F

(LO 31, LO 32, and LO 34)  Which of the following is/are true?  Select all that apply.

1. BaCl is barium chloride

2. ZnBr₂ is zinc(II) bromide

3. Ag₂Cr₂O₇ is silver dichromate

4. NiSO₄ • 7H₂O is nickel sulfate heptahydrate

5. Mn(C₂H₃O₂)₂ • 4H₂O is manganese(II) acetate tetrahydrate

6. PF₅ is monophosphorus pentafluoride

7. N₂O₄ is dinitrogen tetroxide

8. In₂O₃ is diindium trioxide

C, E, and G

(LO 35)  Calculate the number of moles Ca(OH)₂ in 946 dg Ca(OH)₂.

1.28

(LO 35)  How many molecules are contained in 25.0 ng N₂O₅? 

Enter your answer in scientific notation using the following format:  1.00x10¹⁵ would be entered as 1.00E15

1.39E14

(LO 36)  Calculate the percent by mass of oxygen in calcium carbonate hexahydrate.  Enter a number without a % sign.

69.2

(LO 36)  A certain compound is 14.5% F by mass.  If the density of the compound is 4.11 g/mL, how many atoms of F are contained in 9.29 L of the compound?

Enter your answer in scientific notation using the following format:  1.00x10¹⁵ would be entered as 1.00E15

1.74E26

(LO 37)  How many total atoms are contained in 56.0 g C₁₂H₂₄N₄?

Enter your answer in scientific notation using the following format:  1.00x10¹⁵ would be entered as 1.00E15

Answer

6.01E24

LO 38)  A sample from a compound contains 47.3707 g carbon, 5.96373 g hydrogen, and 23.6656 g oxygen.  Its molar mass is about 625 g/mol.  What is its molecular formula?

1. C₂₄H₃₆O₉

2. C₃₀H₄₀O₁₄

3. C₃₄H₅₆O₁₀

4. C₃₆H₆₄O₈

5. C₂₈H₃₂O₁₆

6. C₃₂H₄₈O₁₂

7. C₂₁H₂₄O₁₂

Answer

f

(LO 38)  When a 25.00 g sample of an organic compound containing only carbon, hydrogen, and oxygen undergoes combustion analysis, it produces 52.0530 g CO₂ and 21.3085 g H₂O.  Find the empirical formula for the unknown compound.

1. C₉H₁₆O₂

2. C₄H₈O

3. C₅H₈O

4. C₁₀H₁₈O₃

5. C₃H₈O

6. C₉H₁₄O₂

7. C₉H₁₈O₄

Answer

G

(LO 39 and LO 46)  Which of the following is/are true?  Select all that apply.

1. In a nonpolar covalent bond, electrons are shared equally.

2. C—F bond should be more polar than a N—O bond.

3. C₄H₁₀ is polar

4. H₂CO is polar

5. CH₂F₂ is polar

6. PF₅ is polar

7. XeF₄ is polar

8. SF₄ is polar

A, B, D, E, and H

(LO 43)  Which of the following is/are true?  Select all that apply.

1. N₂H₂ has a shorter bond between the two nitrogen atoms than N₂

2. N₂H₄ has a weaker bond between the two nitrogen atoms than N₂H₂

3. Nitrite has a longer bond between nitrogen and oxygen than CH₃NO

Answer

B and C

(LO 44)  Which of the following is/are true?  Select all that apply. BrF3 has a T-shaped molecular geometry XeF2 has a bent molecular geometry SeF4 has a tetrahedral molecular geometry IF5 has a square pyramidal molecular geometry BF3 has a trigonal planar molecular geometry

A, D, and E

(LO 45)  Complete the Lewis structure for NHCHCH₂CHO by adding lone pairs of electrons.  Which of the following is/are true?

1. The molecular geometry around the bolded atom is bent: NHCHCH₂CHO

2. The molecular geometry around the bolded atom is trigonal pyramidal: NHCHCH₂CHO

3. The molecular geometry around the bolded atom is tetrahedral: NHCHCH₂CHO

4. The molecular geometry around the bolded atom is trigonal planar: NHCHCH₂CHO

Answer

A, C, and D

(LO 40)  Draw the Lewis structure for CH₃OCH₃.  Which of the following is/are true?

1. There are no lone pairs in the Lewis structure.

2. There is one lone pair in the Lewis structure.

3. There are two lone pairs in the Lewis structure.

4. The oxygen atom is bonded to two carbon atoms.

5. The oxygen atom is bonded to one carbon atom.

6. The oxygen atom is bonded to one carbon atom and one hydrogen atom.

7. There are no double bonds.

8. There is one double bond.

9. There are two double bonds.

C, D, and G

(LO 40)  Draw the Lewis structure for hypoiodite.  Which of the following is/are true?

1. There are 2 lone pairs of electrons in the structure.

2. There is 4 lone pair of electrons in the structure.

3. There are 6 lone pairs of electrons in the structure.

4. There are 8 lone pairs of electrons in the structure.

5. There is a single bond in the structure.

6. There is a double bond in the structure.

7. There is a triple bond in the structure.

c and e

(LO 36)  Calculate the percent hydrogen by mass in potassium hydrogen phosphate decahydrate.  Enter a number without a % sign.

Answer

5.97