Question 1

Given the listed average bond energies, calculate the enthalpy change for the production of 48 g of methanol by the reaction: CO₂(g) + 3 H₂(g) → CH₃OH(g) + H₂O(g) C-O/360 kJ/mol C=O/736 kJ/mol H-H/436 kJ/mol H-O/464 kJ/mol H-C/414 kJ/mol

Accepted Answer

The answer of Given the listed average bond energies, calculate...

Question 2

What is the correct molecular geometry for silicon atom in disilane Si₂H₆?

Accepted Answer

The silicon atom in disilane has four electron groups around it (two bonded atoms, one lone pair, and one unpaired electron). This electron group arrangement results in a tetrahedral molecular geometry with bond angles of approximately 109.5 degrees.

Question 3

Given the bond enthalpies C-O (360), C=O (707), O=O (498), H-O (464), C- H (414), all in kJ/mol, estimate ΔH for the following reaction: CH₃OCH₃(g) + 3 O₂(g) → 2 CO₂(g) + 3 H₂O(g).

Accepted Answer

The answer of Given the bond enthalpies C-O (360), C=O...

Question 4

Given the bond enthalpies N-H (389), Cl-Cl (243), N-Cl (201), and H-Cl (431) in kJ/mol, compute ΔH° in kJ/mol for NH₃(g) + Cl₂(g) → NH₂Cl + HCl(g)

Accepted Answer

The answer of Given the bond enthalpies N-H (389), Cl-Cl...

Question 5

Given the listed bond lengths, what would be the most reasonable estimate for the carbon-oxygen bond length in carbon dioxide? C-C/154 pm C=C/120 pm C-O/143 pm O-O/145 pm O=O/121 pm

Accepted Answer

In carbon dioxide (CO2), the carbon and oxygen atoms are connected by double bonds, similar to the C=C and O=O examples given. Since the bond length of C=C is 120 pm and O=O is 121 pm, the C=O bond length in CO2 would be expected to be similar, around 120 pm.

Question 6

Given the following bond lengths in pm: C-C, 154; C = C, 134; Cl - Cl, 199 What is the best estimate of the C-Cl bond length in CCl₄ in pm?

Accepted Answer

The C-Cl bond length can be estimated by averaging the bond lengths of similar single bonds. The C-C single bond is 154 pm and Cl-Cl single bond is 199 pm. The average of these two is (154 + 199) / 2 = 176.5 pm, which is closest to 177 pm.

Question 7

Given the bond enthalpies C=O (707), O=O (498), H-O (464), and C-H (414) in kJ/mol, compute ΔH° in kJ/mol for: CH₄(g) + 2 O₂(g) → CO₂(g) + 2 H₂O(g).

Accepted Answer

The answer of Given the bond enthalpies C=O (707), O=O...

Question 8

Given the bond enthalpies H-O (464), Cl-Cl (243), Cl-O (205), and H-Cl (431) in kJ/mol, compute ΔH° in kJ/mol for H₂O(g) + Cl₂(g) → HOCl(g) + HCl(g).

Accepted Answer

To calculate ΔH°, use the bond enthalpies: ΔH° = Σ(bond enthalpies of reactants) - Σ(bond enthalpies of products). For reactants: H-O (464) + Cl-Cl (243) = 707 kJ/mol. For products: Cl-O (205) + H-Cl (431) = 636 kJ/mol. ΔH° = 707 - 636 = +71 kJ/mol.

Question 9

What is the bond order for the carbon-oxygen bond in formaldehyde (CH₂O), which has no O-H bonds?

Accepted Answer

Formaldehyde has a double bond between the carbon and oxygen atoms. The bond order is equal to the number of bonds between two atoms, so the carbon-oxygen bond in formaldehyde has a bond order of 2.

Question 10

Given the bond enthalpies Cl-Cl (243), C-Cl (339), H-Cl (431),C-H (414) all in kJ/mol, estimate ΔH for the following reaction: CH₄(g) + Cl₂(g) → CH₃Cl(g) + HCl(g)

Accepted Answer

The correct answer is A because the ΔH for the reaction can be calculated as follows:ΔH = Σ(bond enthalpies of reactants) - Σ(bond enthalpies of products)ΔH = [4(H-Cl) + C-H + Cl-Cl] - [3(H-Cl) + C-Cl + C-H]ΔH = [4(431) + 414 + 243] - [3(431) + 339 + 414]ΔH = [1724 + 414 + 243] - [1293 + 339 + 414]ΔH = 2381 - 2046ΔH = -113 kJ

Question 11

Given the bond enthalpies I-Cl (209), H-H (435), H-I (297), and H-Cl (431) in kJ/mol, compute ΔH° in kJ/mol for: ICl₃(g) + 2 H₂(g) → HI(g) + 3 HCl(g)

Accepted Answer

ΔH° = Σ(ΔH°(bonds broken)) - Σ(ΔH°(bonds formed))

Bonds broken: 
1 I-Cl bond = 209 kJ/mol 
2 H-S bonds = 2(435 kJ/mol) = 870 kJ/mol

Bonds formed: 
1 H-I bond = 297 kJ/mol 
3 H-Cl bonds = 3(431 kJ/mol) = 1293 kJ/mol

ΔH° = (209 kJ/mol + 870 kJ/mol) - (297 kJ/mol + 1293 kJ/mol) 
ΔH° = -93 kJ/mol

Therefore, the answer is C.

Question 12

Compound EX4 reacts with Y2 giving two products: EX3Y and XY. Calculate the E-X bond enthalpy if the reaction liberates 243.6 kJ/mol and other bond enthalpies are: Y-Y 109 kJ/mol, X-Y 123.1 kJ/mol and E-Y 290 kJ/mol.

Accepted Answer

The reaction can be represented as: EX4 + Y2 → EX3Y + XY. The bond enthalpy change is calculated using the formula: ΔH = Σ(bonds broken) - Σ(bonds formed). Bonds broken: 1 E-X and 1 Y-Y. Bonds formed: 1 E-Y and 1 X-Y. Solving for E-X bond enthalpy gives 60.5 kJ/mol.

Question 13

Given the bond enthalpies N≡N (946), H-H (436), H-N (389), all in kJ/mol, estimate ΔH for the following reaction: N₂(g) + 3 H₂(g) → 2NH₃(g).

Accepted Answer

The answer of Given the bond enthalpies N≡N (946), H-H...

Question 14

What is the correct molecular geometry for SeBr₃⁺?

Accepted Answer

The SeBr3+ ion has a central selenium atom with three bromine atoms and one positive charge. The molecular geometry is trigonal pyramidal due to the presence of three bonding pairs and one lone pair on the selenium atom.

Question 15

What is the correct molecular geometry for the carbon atom in urea (NH₂)₂CO?

Accepted Answer

The carbon atom in urea is bonded to two nitrogen atoms and one oxygen atom, forming a planar structure with 120-degree bond angles, which is characteristic of trigonal planar geometry.

Question 16

Given the following bond lengths in pm: N-N, 145; N=N, 123; Br-Br, 228 What is the best estimate of the N-Br bond length in NBr₃ in pm?

Accepted Answer

The N-Br bond length can be estimated by adding the covalent radii of N and Br. The N-N single bond length is 145 pm, suggesting a covalent radius for N of about 72.5 pm. The Br-Br bond length is 228 pm, suggesting a covalent radius for Br of about 114 pm. Adding these gives an estimated N-Br bond length of approximately 187 pm.

Question 17

Given the bond enthalpies C=C (611), C≡C (837), H-H (436),C-H (414) all in kJ/mol, estimate ΔH for the following reaction: C₂H₂(g) + H₂(g) → C₂H₄(g)

Accepted Answer

The answer of Given the bond enthalpies C=C (611), C≡C...

Quiz 10: Chemical Bonding I: Basic Concepts

Given the listed average bond energies, calculate the enthalpy change for the production of 48 g of methanol by the reaction: CO₂(g) + 3 H₂(g) → CH₃OH(g) + H₂O(g) C-O/360 kJ/mol C=O/736 kJ/mol H-H/436 kJ/mol H-O/464 kJ/mol H-C/414 kJ/mol

What is the correct molecular geometry for silicon atom in disilane Si₂H₆?

Given the bond enthalpies C-O (360) , C=O (707) , O=O (498) , H-O (464) , C- H (414) , all in kJ/mol, estimate ΔH for the following reaction: CH₃OCH₃(g) + 3 O₂(g) → 2 CO₂(g) + 3 H₂O(g) .

Given the bond enthalpies N-H (389) , Cl-Cl (243) , N-Cl (201) , and H-Cl (431) in kJ/mol, compute ΔH° in kJ/mol for NH₃(g) + Cl₂(g) → NH₂Cl + HCl(g)

Given the listed bond lengths, what would be the most reasonable estimate for the carbon-oxygen bond length in carbon dioxide? C-C/154 pm C=C/120 pm C-O/143 pm O-O/145 pm O=O/121 pm

Given the following bond lengths in pm: C-C, 154; C = C, 134; Cl - Cl, 199 What is the best estimate of the C-Cl bond length in CCl₄ in pm?

Given the bond enthalpies C=O (707) , O=O (498) , H-O (464) , and C-H (414) in kJ/mol, compute ΔH° in kJ/mol for: CH₄(g) + 2 O₂(g) → CO₂(g) + 2 H₂O(g) .

Given the bond enthalpies H-O (464) , Cl-Cl (243) , Cl-O (205) , and H-Cl (431) in kJ/mol, compute ΔH° in kJ/mol for H₂O(g) + Cl₂(g) → HOCl(g) + HCl(g) .

What is the bond order for the carbon-oxygen bond in formaldehyde (CH₂O) , which has no O-H bonds?

Given the bond enthalpies Cl-Cl (243) , C-Cl (339) , H-Cl (431) ,C-H (414) all in kJ/mol, estimate ΔH for the following reaction: CH₄(g) + Cl₂(g) → CH₃Cl(g) + HCl(g)

Given the bond enthalpies I-Cl (209) , H-H (435) , H-I (297) , and H-Cl (431) in kJ/mol, compute ΔH° in kJ/mol for: ICl₃(g) + 2 H₂(g) → HI(g) + 3 HCl(g)

Compound EX4 reacts with Y2 giving two products: EX3Y and XY. Calculate the E-X bond enthalpy if the reaction liberates 243.6 kJ/mol and other bond enthalpies are: Y-Y 109 kJ/mol, X-Y 123.1 kJ/mol and E-Y 290 kJ/mol.

Given the bond enthalpies N≡N (946) , H-H (436) , H-N (389) , all in kJ/mol, estimate ΔH for the following reaction: N₂(g) + 3 H₂(g) → 2NH₃(g) .

What is the correct molecular geometry for SeBr₃⁺?

What is the correct molecular geometry for the carbon atom in urea (NH₂) ₂CO?

Given the following bond lengths in pm: N-N, 145; N=N, 123; Br-Br, 228 What is the best estimate of the N-Br bond length in NBr₃ in pm?

Given the bond enthalpies C=C (611) , C≡C (837) , H-H (436) ,C-H (414) all in kJ/mol, estimate ΔH for the following reaction: C₂H₂(g) + H₂(g) → C₂H₄(g)

Quiz 10: Chemical Bonding I: Basic Concepts

Given the listed average bond energies, calculate the enthalpy change for the production of 48 g of methanol by the reaction: CO2(g) + 3 H2(g) → CH3OH(g) + H2O(g) C-O/360 kJ/mol C=O/736 kJ/mol H-H/436 kJ/mol H-O/464 kJ/mol H-C/414 kJ/mol

What is the correct molecular geometry for silicon atom in disilane Si2H6?

Given the bond enthalpies C-O (360) , C=O (707) , O=O (498) , H-O (464) , C- H (414) , all in kJ/mol, estimate ΔH for the following reaction: CH3OCH3(g) + 3 O2(g) → 2 CO2(g) + 3 H2O(g) .

Given the bond enthalpies N-H (389) , Cl-Cl (243) , N-Cl (201) , and H-Cl (431) in kJ/mol, compute ΔH° in kJ/mol for NH3(g) + Cl2(g) → NH2Cl + HCl(g)

Given the listed bond lengths, what would be the most reasonable estimate for the carbon-oxygen bond length in carbon dioxide? C-C/154 pm C=C/120 pm C-O/143 pm O-O/145 pm O=O/121 pm

Given the following bond lengths in pm: C-C, 154; C = C, 134; Cl - Cl, 199 What is the best estimate of the C-Cl bond length in CCl4 in pm?

Given the bond enthalpies C=O (707) , O=O (498) , H-O (464) , and C-H (414) in kJ/mol, compute ΔH° in kJ/mol for: CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g) .

Given the bond enthalpies H-O (464) , Cl-Cl (243) , Cl-O (205) , and H-Cl (431) in kJ/mol, compute ΔH° in kJ/mol for H2O(g) + Cl2(g) → HOCl(g) + HCl(g) .

What is the bond order for the carbon-oxygen bond in formaldehyde (CH2O) , which has no O-H bonds?

Given the bond enthalpies Cl-Cl (243) , C-Cl (339) , H-Cl (431) ,C-H (414) all in kJ/mol, estimate ΔH for the following reaction: CH4(g) + Cl2(g) → CH3Cl(g) + HCl(g)

Given the bond enthalpies I-Cl (209) , H-H (435) , H-I (297) , and H-Cl (431) in kJ/mol, compute ΔH° in kJ/mol for: ICl3(g) + 2 H2(g) → HI(g) + 3 HCl(g)

Compound EX4 reacts with Y2 giving two products: EX3Y and XY. Calculate the E-X bond enthalpy if the reaction liberates 243.6 kJ/mol and other bond enthalpies are: Y-Y 109 kJ/mol, X-Y 123.1 kJ/mol and E-Y 290 kJ/mol.

Given the bond enthalpies N≡N (946) , H-H (436) , H-N (389) , all in kJ/mol, estimate ΔH for the following reaction: N2(g) + 3 H2(g) → 2NH3(g) .

What is the correct molecular geometry for SeBr3+?

What is the correct molecular geometry for the carbon atom in urea (NH2) 2CO?

Given the following bond lengths in pm: N-N, 145; N=N, 123; Br-Br, 228 What is the best estimate of the N-Br bond length in NBr3 in pm?

Given the bond enthalpies C=C (611) , C≡C (837) , H-H (436) ,C-H (414) all in kJ/mol, estimate ΔH for the following reaction: C2H2(g) + H2(g) → C2H4(g)

Given the listed average bond energies, calculate the enthalpy change for the production of 48 g of methanol by the reaction: CO₂(g) + 3 H₂(g) → CH₃OH(g) + H₂O(g) C-O/360 kJ/mol C=O/736 kJ/mol H-H/436 kJ/mol H-O/464 kJ/mol H-C/414 kJ/mol

What is the correct molecular geometry for silicon atom in disilane Si₂H₆?

Given the bond enthalpies C-O (360) , C=O (707) , O=O (498) , H-O (464) , C- H (414) , all in kJ/mol, estimate ΔH for the following reaction: CH₃OCH₃(g) + 3 O₂(g) → 2 CO₂(g) + 3 H₂O(g) .

Given the bond enthalpies N-H (389) , Cl-Cl (243) , N-Cl (201) , and H-Cl (431) in kJ/mol, compute ΔH° in kJ/mol for NH₃(g) + Cl₂(g) → NH₂Cl + HCl(g)

Given the following bond lengths in pm: C-C, 154; C = C, 134; Cl - Cl, 199 What is the best estimate of the C-Cl bond length in CCl₄ in pm?

Given the bond enthalpies C=O (707) , O=O (498) , H-O (464) , and C-H (414) in kJ/mol, compute ΔH° in kJ/mol for: CH₄(g) + 2 O₂(g) → CO₂(g) + 2 H₂O(g) .

Given the bond enthalpies H-O (464) , Cl-Cl (243) , Cl-O (205) , and H-Cl (431) in kJ/mol, compute ΔH° in kJ/mol for H₂O(g) + Cl₂(g) → HOCl(g) + HCl(g) .

What is the bond order for the carbon-oxygen bond in formaldehyde (CH₂O) , which has no O-H bonds?

Given the bond enthalpies Cl-Cl (243) , C-Cl (339) , H-Cl (431) ,C-H (414) all in kJ/mol, estimate ΔH for the following reaction: CH₄(g) + Cl₂(g) → CH₃Cl(g) + HCl(g)

Given the bond enthalpies I-Cl (209) , H-H (435) , H-I (297) , and H-Cl (431) in kJ/mol, compute ΔH° in kJ/mol for: ICl₃(g) + 2 H₂(g) → HI(g) + 3 HCl(g)

Given the bond enthalpies N≡N (946) , H-H (436) , H-N (389) , all in kJ/mol, estimate ΔH for the following reaction: N₂(g) + 3 H₂(g) → 2NH₃(g) .

What is the correct molecular geometry for SeBr₃⁺?

What is the correct molecular geometry for the carbon atom in urea (NH₂) ₂CO?

Given the following bond lengths in pm: N-N, 145; N=N, 123; Br-Br, 228 What is the best estimate of the N-Br bond length in NBr₃ in pm?

Given the bond enthalpies C=C (611) , C≡C (837) , H-H (436) ,C-H (414) all in kJ/mol, estimate ΔH for the following reaction: C₂H₂(g) + H₂(g) → C₂H₄(g)