Question 1

The formal charge on nitrogen in NO₃^- is ________, where the Lewis structure of the ion is:

Accepted Answer

To determine the formal charge on nitrogen, we need to know the valence electrons of nitrogen in the Lewis structure and how many valence electrons nitrogen is actually bearing in the ion. 
From the Lewis structure of the ion, we can see that nitrogen is directly bonded to one oxygen and one sulfur atom. Nitrogen is also bonded to one other oxygen atom but through a coordinate covalent bond from its lone pair of electrons. Hence, nitrogen is sharing 6 electrons in the form of three pairs: 1 with sulfur, 2 with oxygen and 1 with the coordinate covalent bond. 
The valence electrons of nitrogen are 5. But in the ion, nitrogen is sharing 6 electrons. Therefore, the formal charge on nitrogen is 5 - 6 = -1. 
Thus, the correct answer is C.

Question 2

In the Lewis structure of ClF, the formal charge on Cl is ________, and the formal charge on F is ________.

Accepted Answer

In the Lewis structure of ClF, chlorine (Cl) and fluorine (F) form a single bond. Chlorine has 7 valence electrons and fluorine has 7 valence electrons. When they form a single bond, each contributes one electron to the bond, leaving chlorine and fluorine with 6 and 6 non-bonding electrons, respectively. The formal charge is calculated as the number of valence electrons in the free atom minus the number of non-bonding electrons minus half the number of bonding electrons. For both Cl and F, this calculation results in a formal charge of 0, indicating that both atoms have no formal charge in the ClF molecule.

Question 3

Using the table of bond dissociation energies, the ΔH for the following gas-phase reaction is ________ kJ.

Accepted Answer

The answer of Using the table of bond dissociation energies,...

Question 4

Using the table of bond dissociation energies, the ΔH for the following gas-phase reaction is ________ kJ.

Accepted Answer

The ΔH for the reaction is equal to the sum of the bond dissociation energies of the bonds broken minus the sum of the bond dissociation energies of the bonds formed.

Breaking bonds:
4C-H bonds: 4 x 413 kJ/mol = 1652 kJ/mol
2C-C bonds: 2 x 347 kJ/mol = 694 kJ/mol
1C=C bond: 839 kJ/mol

Forming bonds:
3C=C bonds: 3 x 603 kJ/mol = 1809 kJ/mol
4H-H bonds: 4 x 436 kJ/mol = 1744 kJ/mol

ΔH = (1652 kJ/mol + 694 kJ/mol + 839 kJ/mol) - (1809 kJ/mol + 1744 kJ/mol) 
ΔH = -57 kJ/mol

Therefore, the best choice is C, -57.

Question 5

How many different types of resonance structures can be drawn for the ion SO₃^2- where all atoms satisfy the octet rule?

Accepted Answer

The ion SO₃^2- has three resonance structures, all of which satisfy the octet rule.

Question 6

How many equivalent resonance structures can be drawn for the molecule of SO₃ without having to violate the octet rule on the sulfur atom?

Accepted Answer

The molecule SO₃, when interpreted correctly as SO3, has three equivalent resonance structures. These structures involve the sulfur atom double-bonded to each of the three oxygen atoms in turn, with the other two oxygens carrying a negative charge and the sulfur atom having a formal positive charge. This arrangement allows for the depiction of the delocalized pi electrons among the sulfur and oxygen atoms without violating the octet rule for sulfur.

Question 7

The Lewis structure of PF₃ shows that the central phosphorus atom has ________ nonbonding and ________ bonding electron pair(s).

Accepted Answer

Phosphorus in PFS (assuming a typo and it should be PF5) has 5 valence electrons. In PF5, all 5 electrons are used to form bonds with 5 fluorine atoms, leaving no nonbonding electrons on phosphorus. However, the question seems to contain a typo or encoding error (PF₃), which complicates direct interpretation. Assuming the intended molecule is PF5, based on typical valence and bonding patterns, phosphorus would have 1 nonbonding pair (due to the error in the question, but actually it should have 0) and 3 bonding pairs in a simplified or mistaken interpretation. However, correctly, PF5 has no nonbonding pairs and 5 bonding pairs. Given the options and likely errors in the question, the closest match under a misunderstanding would be 1 nonbonding and 3 bonding, but this does not accurately reflect PF5's structure. The response is based on interpreting the question's intent rather than accurate chemical principles due to the apparent errors.

Question 8

In the Lewis structure of HCO₃^-, the formal charge on H is ________, and the formal charge on C is ________.

Accepted Answer

The formal charge on an atom in a molecule can be calculated using the formula: Formal charge = (Valence electrons) - (Non-bonding electrons) - 1/2(Bonding electrons). For hydrogen (H), it typically has 1 valence electron, forms 1 bond, and has no lone pairs, leading to a formal charge of 0. For carbon (C), it has 4 valence electrons, forms 4 bonds in this molecule (assuming a typical bonding scenario for a Lewis structure involving C, H, O, and S), and has no lone pairs, leading to a formal charge of 0 as well.

Question 9

The formal charge on sulfur in SO₄^2- is ________, where the Lewis structure of the ion is:

Accepted Answer

The answer of The formal charge on sulfur in SO₄^2-...

Question 10

In the resonance form of ozone shown below, the formal charge on the central oxygen atom is ________.

Accepted Answer

The answer of In the resonance form of ozone shown...

Question 11

The Lewis structure of HCN (H bonded toC)shows that ________ has ________ nonbonding electron pair(s).

Accepted Answer

The Lewis structure of HCN shows that N has one nonbonding electron pair. C and H do not have any nonbonding electron pairs in this molecule.

Question 12

How many equivalent resonance forms can be drawn for CO₃^2-? (Carbon is the central atom.)

Accepted Answer

To determine the number of equivalent resonance forms for a molecule, we need to identify the number of possible ways in which we can move electrons in the molecule while maintaining the overall connectivity and hybridization. For CO₃^2-, we can move the lone pairs on the sulfur or oxygen atoms onto the neighboring atoms to form pi-bonds. We can also move the pi-bond electrons onto the neighboring atoms to form lone pairs. By doing so, we can draw three equivalent resonance forms as shown below: S O P ║ ║ ║ C=O C=S C-P+ ║ ║ ║ S O S Thus, the answer is (C) 3.

Question 13

Using the table of average bond energies below, the ΔH for the reaction is ________ kJ. H-C≡C-H (g) + H-I (g) → H₂C CHI (g) Bond: C≡C C=C H-I C-I C-H D (kJ/mol): 839 614 299 240 413

Accepted Answer

The answer of Using the table of average bond energies...

Question 14

How many equivalent resonance forms can be drawn for SO₂ without expanding octet on the sulfur atom? (Sulfur is the central atom.)

Accepted Answer

SO₂ has two equivalent resonance forms where one of the oxygen atoms forms a double bond with sulfur, and the other oxygen has a single bond with sulfur, with the negative charge on the singly bonded oxygen. These forms are equivalent due to the symmetry of the molecule.

Question 15

The ________ ion has a noble gas electron configuration.

Accepted Answer

The answer of The ________ ion has a noble gas...

Question 16

Using the table of bond dissociation energies, the ΔH for the following reaction is ________ kJ. 2HCl (g) + F₂ (g) → 2HF (g) + Cl₂ (g)

Accepted Answer

The answer of Using the table of bond dissociation energies,...

Question 17

There are ________ paired and ________ unpaired electrons in the Lewis symbol for a fluorine atom.

Accepted Answer

Fluorine has 7 valence electrons: 6 of them form 3 pairs, and 1 remains unpaired, making the correct answer 6 paired and 1 unpaired.

Question 18

Using the table of average bond energies below, the △H for the reaction is ________ kJ. C≡O (g) + 2H₂ (g) → H₃C-O-H (g) Bond: C-O C=O C≡O C-H H-H O-H D (kJ/mol): 358 799 1072 413 436 463

Accepted Answer

The answer of Using the table of average bond energies...

Question 19

Using the table of average bond energies below, the ΔH for the reaction is ________ kJ.  Bond: C≡C C-C H-I C-I C-H D (kJ/mol): 839 348 299 240 413

Accepted Answer

The ΔH for the reaction can be calculated using the following formula:

ΔH = Σ(bond energies of reactants) - Σ(bond energies of products)

The balanced chemical equation for the reaction is not given, so let's assume it involves the breaking of one C≡C bond and the formation of one C-I bond and one H-I bond.

Reactants:
C≡C (1 bond) : 839 kJ/mol
H-I (1 bond) : 299 kJ/mol

Products:
C-I (1 bond) : 240 kJ/mol
C-H (1 bond) : 413 kJ/mol

ΔH = (839 kJ/mol + 299 kJ/mol) - (240 kJ/mol + 413 kJ/mol) = -217 kJ/mol

Therefore, the answer is C, -217.

Question 20

The formal charge on carbon in the molecule below is ________.

Accepted Answer

The answer of The formal charge on carbon in the...

Quiz 8: Basic Concepts of Chemical Bonding

The formal charge on nitrogen in NO₃^- is ________, where the Lewis structure of the ion is:

In the Lewis structure of ClF, the formal charge on Cl is , and the formal charge on F is .

Using the table of bond dissociation energies, the ΔH for the following gas-phase reaction is ________ kJ.

Using the table of bond dissociation energies, the ΔH for the following gas-phase reaction is ________ kJ.

How many different types of resonance structures can be drawn for the ion SO₃^2- where all atoms satisfy the octet rule?

How many equivalent resonance structures can be drawn for the molecule of SO₃ without having to violate the octet rule on the sulfur atom?

The Lewis structure of PF₃ shows that the central phosphorus atom has nonbonding and bonding electron pair(s) .

In the Lewis structure of HCO₃^-, the formal charge on H is , and the formal charge on C is .

The formal charge on sulfur in SO₄^2- is ________, where the Lewis structure of the ion is:

In the resonance form of ozone shown below, the formal charge on the central oxygen atom is ________.

The Lewis structure of HCN (H bonded toC) shows that has nonbonding electron pair(s) .

How many equivalent resonance forms can be drawn for CO₃^2-? (Carbon is the central atom.)

Using the table of average bond energies below, the ΔH for the reaction is ________ kJ. H-C≡C-H (g) + H-I (g) → H₂C CHI (g) Bond: C≡C C=C H-I C-I C-H D (kJ/mol) : 839 614 299 240 413

How many equivalent resonance forms can be drawn for SO₂ without expanding octet on the sulfur atom? (Sulfur is the central atom.)

The ________ ion has a noble gas electron configuration.

Using the table of bond dissociation energies, the ΔH for the following reaction is ________ kJ. 2HCl (g) + F₂ (g) → 2HF (g) + Cl₂ (g)

There are paired and unpaired electrons in the Lewis symbol for a fluorine atom.

Using the table of average bond energies below, the △H for the reaction is ________ kJ. C≡O (g) + 2H₂ (g) → H₃C-O-H (g) Bond: C-O C=O C≡O C-H H-H O-H D (kJ/mol) : 358 799 1072 413 436 463

Using the table of average bond energies below, the ΔH for the reaction is ________ kJ. Bond: C≡C C-C H-I C-I C-H D (kJ/mol) : 839 348 299 240 413

The formal charge on carbon in the molecule below is ________.

Quiz 8: Basic Concepts of Chemical Bonding

The formal charge on nitrogen in NO3- is ________, where the Lewis structure of the ion is:

In the Lewis structure of ClF, the formal charge on Cl is ________, and the formal charge on F is ________.

Using the table of bond dissociation energies, the ΔH for the following gas-phase reaction is ________ kJ.

Using the table of bond dissociation energies, the ΔH for the following gas-phase reaction is ________ kJ.

How many different types of resonance structures can be drawn for the ion SO32- where all atoms satisfy the octet rule?

How many equivalent resonance structures can be drawn for the molecule of SO3 without having to violate the octet rule on the sulfur atom?

The Lewis structure of PF3 shows that the central phosphorus atom has ________ nonbonding and ________ bonding electron pair(s) .

In the Lewis structure of HCO3-, the formal charge on H is ________, and the formal charge on C is ________.

The formal charge on sulfur in SO42- is ________, where the Lewis structure of the ion is:

In the resonance form of ozone shown below, the formal charge on the central oxygen atom is ________.

The Lewis structure of HCN (H bonded toC) shows that ________ has ________ nonbonding electron pair(s) .

How many equivalent resonance forms can be drawn for CO32-? (Carbon is the central atom.)

Using the table of average bond energies below, the ΔH for the reaction is ________ kJ. H-C≡C-H (g) + H-I (g) → H2C CHI (g) Bond: C≡C C=C H-I C-I C-H D (kJ/mol) : 839 614 299 240 413

How many equivalent resonance forms can be drawn for SO2 without expanding octet on the sulfur atom? (Sulfur is the central atom.)

The ________ ion has a noble gas electron configuration.

Using the table of bond dissociation energies, the ΔH for the following reaction is ________ kJ. 2HCl (g) + F2 (g) → 2HF (g) + Cl2 (g)

There are ________ paired and ________ unpaired electrons in the Lewis symbol for a fluorine atom.

Using the table of average bond energies below, the △H for the reaction is ________ kJ. C≡O (g) + 2H2 (g) → H3C-O-H (g) Bond: C-O C=O C≡O C-H H-H O-H D (kJ/mol) : 358 799 1072 413 436 463

Using the table of average bond energies below, the ΔH for the reaction is ________ kJ. Bond: C≡C C-C H-I C-I C-H D (kJ/mol) : 839 348 299 240 413

The formal charge on carbon in the molecule below is ________.

The formal charge on nitrogen in NO₃^- is ________, where the Lewis structure of the ion is:

In the Lewis structure of ClF, the formal charge on Cl is , and the formal charge on F is .

How many different types of resonance structures can be drawn for the ion SO₃^2- where all atoms satisfy the octet rule?

How many equivalent resonance structures can be drawn for the molecule of SO₃ without having to violate the octet rule on the sulfur atom?

The Lewis structure of PF₃ shows that the central phosphorus atom has nonbonding and bonding electron pair(s) .

In the Lewis structure of HCO₃^-, the formal charge on H is , and the formal charge on C is .

The formal charge on sulfur in SO₄^2- is ________, where the Lewis structure of the ion is:

The Lewis structure of HCN (H bonded toC) shows that has nonbonding electron pair(s) .

How many equivalent resonance forms can be drawn for CO₃^2-? (Carbon is the central atom.)

Using the table of average bond energies below, the ΔH for the reaction is ________ kJ. H-C≡C-H (g) + H-I (g) → H₂C CHI (g) Bond: C≡C C=C H-I C-I C-H D (kJ/mol) : 839 614 299 240 413

How many equivalent resonance forms can be drawn for SO₂ without expanding octet on the sulfur atom? (Sulfur is the central atom.)

Using the table of bond dissociation energies, the ΔH for the following reaction is ________ kJ. 2HCl (g) + F₂ (g) → 2HF (g) + Cl₂ (g)

There are paired and unpaired electrons in the Lewis symbol for a fluorine atom.

Using the table of average bond energies below, the △H for the reaction is ________ kJ. C≡O (g) + 2H₂ (g) → H₃C-O-H (g) Bond: C-O C=O C≡O C-H H-H O-H D (kJ/mol) : 358 799 1072 413 436 463