Chemistry Exam 2

Using the provided table and the equation below, determine the heat of formation (in kJ/mol) for PbS. 2 PbS (s) + 3 O₂ (g) → 2 SO₂ (g) + 2 PbO (s) ∆H° = -828.4 kJ/mol Substance ∆Hf° (kJ/mol) O₂ (g) 0 SO₂ (g) -296.9 PbO (s) -217.3

-100.0 kJ/mol

Using the provided table, determine the molar enthalpy (in kJ/mol) for the reaction 2 NH₃ (g) + 3 N₂O (g)→ 4 N₂ (g) + 3 H₂O (l) Substance ∆Hf° (kJ/mol) NH₃ (g) -46.2 N₂O (g) 81.6 N₂ (g) 0 H₂O (l)

-1009.8 kJ/mol

Calculate the enthalpy of combustion (kJ/mol) of methyl linoleate (C₁₉H₃₄O₂), an important component of many biodiesel fuels made from corn oil and methanol, given the following standard enthalpies of formation: CO₂(g) = -393.5 kJ/mol H₂O(l) = -285.8 kJ/mol C₁₉H₃₄O₂(l) = -645.7 kJ/mol

-11689 kJ/mol

Calculate the enthalpy of combustion (kJ/mol) of ethyl stearate (C₂₀H₄₀O₂), an important component of many biodiesel fuels made from soybean oil and ethanol, given the following standard enthalpies of formation: CO₂(g) = -393.5 kJ/mol H₂O(l) = -285.8 kJ/mol C₂₀H₄₀O₂(l) = -984.6 kJ/mol

-12601 kJ/mol

The molar enthalpy of combustion of acetylene (C₂H₂) gas in oxygen is given below, in the following chemical equation. What is the total enthalpy change in kJ resulting from the complete combustion of 5.313 g C₂H₂ (acetylene)? 2 C₂H₂(g) + 5 O₂(g) → 4 CO₂(g) + 2 H₂O(g) ∆H = -1299 kJ 5.313 g C₂H₂

-132.5 kJ

Using the provided table, determine the molar enthalpy (in kJ/mol) for the reaction C₃H₈ (g) + 5 O₂ (g) → 3 CO₂ (g) + 4 H₂O (g) Substance ∆Hf° (kJ/mol) C₃H₈ (g) -108.4 O₂ (g) 0 CO₂ (g) -393.5 H₂O (g)

-2039.3 kJ/mol

For the chemical reaction H₂ (g) + F₂ (g) → 2 HF (g) ∆H° = -79.2 kJ/mol. What is the molar enthalpy (in kJ/mol) for the reaction 3 H₂ (g) + 3 F₂ (g) → 6 HF (g)

-238 kJ/mol

What is the change in enthalpy when 1.50 moles of H₂ are reacted with an excess O₂ of according to the following balanced chemical reaction: 2 H₂(g) + O₂(g) → 2 H₂O(l) ∆H =-572 kJ 1.50 mol H₂

-429 kJ

What is the missing value in the table below? Reaction ∆H (kJ/mol) A → B -10 B → C 5 A → C ?

-5 kJ/mol

Determine the enthalpy of reaction for P₄O₁₀(s) + 6PCl₅(g) → 10POCl₃(g) P₄(s) + 6Cl₂(g) → 4PCl₃(g) ∆H° = -1225.6 kJ/mol P₄(s) + 5O₂(g) → P₄O₁₀(s) ∆H° = -2967.3 kJ/mol PCl₃(g) + Cl₂(g) → PCl₅(g) ∆H° = -84.2 kJ/mol PCl₃(g) + ½O₂(g) → POCl₃(g) ∆H° = -285.72 kJ/mol

-610.3 kJ/mol

What is the change in enthalpy when 1.25 moles of O₂ are reacted with an excess H₂ of according to the following balanced chemical reaction: 2 H₂(g) + O₂(g) → 2 H₂O(l) ∆H = -572 kJ 1.25 mol O₂

-715 kJ

Using the equations N₂ (g) + O₂ (g) → 2 NO (g) ∆H° = 180.6 kJ/mol N₂ (g) + 3 H₂ (g) → 2 NH₃ (g) ∆H° = -91.8 kJ/mol 2 H₂ (g) + O₂ (g) → 2 H₂O (g) ∆H° = -483.7 kJ/mol Determine the molar enthalpy (in kJ/mol) for the reaction 4 NH₃ (g) + 5 O₂ (g) → 4 NO (g) + 6 H₂O (g).

-906.3 kJ/mol

How many moles of C₆H₁₂ (cyclohexane) must be reacted according to the following balanced chemical reaction to transfer -419. kJ of heat? C₆H₁₂(l) + 9 O₂(g) → 6 CO₂(g) + 6 H₂O(g) ∆H = -3919.4 kJ -

0.1069m C₆H₁₂

What is the maximum number of electrons that can have the following set of quantum numbers? n = 4, ℓ = 3, mℓ = 1, ms = -½

1

What is the value of ℓ for the orbital shown below?

1

What is the frequency of a photon if the energy is 7.03 × 10⁻¹⁹ J? (h = 6.626 × 10⁻³⁴ J • s)

1.06 × 10¹⁵ s⁻¹

For the chemical reaction Ca (s) + ½ O₂ (g) → CaO (s) ∆H° = -635 kJ/mol. What is the molar enthalpy (in kJ/mol) for the reaction 2 CaO (s) → 2 Ca (s) + O₂ (g)?

1270 kJ/mol

The steam reforming of methane occurs according to the following chemical equation: CH₄(g) + 2H₂O(g) ⇌ CO₂(g) + 4H₂(g) Use the following equations to solve for the enthalpy change of steam reforming of methane: H₂(g) + ½O₂(g) → H₂O(g) ∆H° = -242 kJ/mol 2H₂(g) + C(s) → CH₄(g) ∆H° = -75 kJ/mol C(s) + O₂(g) → CO₂(g) ∆H° = -394 kJ/mol

165 kJ/mol

Write the complete ground-state electron configuration of B. For multi-digit superscripts or coefficients, use each number in succession.

1s²2s²2p¹

Write the complete ground-state electron configuration of N³⁻. For multi-digit superscripts or coefficients, use each number in succession.

1s²2s²2p⁶

Write the complete ground-state electron configuration of O²⁻. For multi-digit superscripts or coefficients, use each number in succession.

1s²2s²2p⁶

Write the complete ground-state electron configuration of Mn²⁺. For multi-digit superscripts or coefficients, use each number in succession.

1s²2s²2p⁶3s²3p⁶3d⁵

Write the complete ground-state electron configuration of arsenic. For multi-digit superscripts or coefficients, use each number in succession.

1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p³

Write the complete ground-state electron configuration of Sn. For multi-digit superscripts or coefficients, use each number in succession.

1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p²

What is a value of ℓ for the orbital shown below?

2

What is the de Broglie wavelength (in meters) of a 58.1 g tennis ball when served at a velocity of 43.5 meters per second?

2.62 × 10⁻³⁴ m

If n = 4, what is the maximum allowed value for ℓ?

3

Using the equations 2 Fe (s) + 3 Cl₂ (g) → 2 FeCl₃ (s) ∆H° = -800.0 kJ/mol Si(s) + 2 Cl₂ (g) → SiCl₄ (s) ∆H° = -640.1 kJ/mol Determine the molar enthalpy (in kJ/mol) for the reaction 3 SiCl₄ (s) + 4 Fe (s) → 4 FeCl₃ (s) + 3 Si (s)

320.3 kJ/mol

Calculate the frequency in hertz of electromagnetic radiation that has a wavelength of 635.0 nm. (c = 3.00 X 10⁸ m/s)

4.72 × 10¹⁴ s⁻¹

Neutron diffraction, like X-ray diffraction, is useful in some kinds of structure determinations. What is the de Broglie wavelength of a neutron (mass = 1.009 amu) moving at a velocity of 8.01 × 10⁶ meters per second?

4.94 × 10⁻¹⁴ m

Calculate the wavelength in meters of electromagnetic radiation that has a frequency of 710.0 kHz. (c = 3.00 X 10⁸ m/s)

422.5 m

Determine the energy, in J, of a photon with a wavelength of 365 nm. (h = 6.626 × 10⁻³⁴ J • s and c = 3.00 × 10⁸ m/s)

5.45 × 10⁻¹⁹ J

Using the equations 2 Sr(s) + O₂ (g) → 2 SrO (s) ∆H° = -1184 kJ/mol CO₂ (g) → C (s) + O₂ (g) ∆H° = 394 kJ/mol Determine the molar enthalpy (in kJ/mol) for the reaction C(s) + 2 SrO(s) → CO₂ (g) + 2 Sr(s).

790 kJ/mol

In one atom, what is the maximum number of electrons that could have the quantum number of n = 2?

8 electrons

How many g CH₄ (methane) must be fully combusted according to the following reaction to transfer -547 kJ of heat? CH₄(g) + 2 O₂(g)→ CO₂(g) + 2 H₂O(g) ∆H = -882 kJ

9.95 g CH₄

For which one of the following is the enthalpy of the reaction the same as the enthalpy of formation? A) 2 Fe (s) + ³/₂ O₂ (g) → Fe₂O₃ (s) B) HCl (aq) + NH₃ (g) → NH₄Cl (s) C) AsF₃ (s) → As (s) + ³/₂ F₂ (g) D) N₂ (g) + 3 H₂ (g) → 2 NH₃ (g)

A) 2 Fe (s) + ³/₂ O₂ (g) → Fe₂O₃ (s)

Which of the following is an example of an ionic bond?

A) K - F

Which of the following atoms would have the longest de Broglie wavelength, if all have the same velocity? A) Li B) Na C) Fe D) Pb E) Not possible to tell with given information

A) Li

What type of light on the electromagnetic spectrum has the lowest energy per photon? A) Radio waves B) Visible light C) All light has the same energy D) Microwaves E) Gamma waves

A) Radio waves

Rank the following atoms in order of decreasing size (i.e., largest to smallest): Rb, F, Mg, B, N. A) Rb > Mg > B > N > F B) N > F > B > Mg > Rb C) Rb > Mg > F > N > B D) Mg > Rb > B > N > F E) Rb > Mg > N > B > F

A) Rb > Mg > B > N > F

In each pair, choose the atom or ion which has the appropriate property based on its position in the Periodic Table. Highest ionization energy A) Rb⁺ B) Sr⁺

A) Rb⁺

Which of the following oxides is predicted to form the most basic aqueous solution? A) Rb₂O B) In₂O₃ C) Al₂O₃ D) SnO₂ E) TeO₂

A) Rb₂O

True or false: two electrons can simultaneously occupy the same (n,ℓ,mℓ) orbital. A) True B) False

A) True

A ground state atom of Mg could not have any electrons with which of the following configurations? A) n = 3, ℓ = 1, mℓ = 0, ms = +½ B) n = 2, ℓ = 1, mℓ = 0, ms = +½ C) n = 3, ℓ = 0, mℓ = 0, ms = +½ D) n = 2, ℓ = 0, mℓ = 0, ms = +½ E) n = 1, ℓ = 0, mℓ = 0, ms = +½

A) n = 3, ℓ = 1, mℓ = 0, ms = +½

If ℓ = 0, which of the following may be true? A) n = 6 B) mℓ = -1 C) mℓ = 1 D) ms = 1 E) ms = 0

A) n = 6

Which of the following has four valence electrons? A) silicon B) neon C) beryllium D) boron

A) silicon

A lattice formation enthalpy (lattice energy) is A) the amount of energy released when individual gaseous ions combine to form an ionic solid. B) the energy released in the formation of a chemical bond. C) the difference in ionization energy and electron affinity of the anion and cation. D) the energy required to convert a substance from a solid to a gaseous state.

A) the amount of energy released when individual gaseous ions combine to form an ionic solid.

Which of the following pairs of ions represent isoelectronic species? A) Na⁺ and N²⁻ B) Al³⁺ and O²⁻ C) K⁺ and Na⁺ D) Cl⁻ and F⁻ E) Al³⁺ and P³⁻

B) Al³⁺ and O²⁻

In each pair, choose the atom or ion which has the appropriate property based on its position in the Periodic Table. Smallest size A) Cs⁺ B) Ba²⁺

B) Ba²⁺

Which of the following radii comparisons is incorrect? A) Sr²⁺ < Sr B) Br⁻ < Br C) Fe³⁺ < Fe²⁺ D) Se²⁻ > Se E) Sn²⁺ > Sn⁴⁺

B) Br⁻ < Br

The energy released in the reaction F(g) + e⁻ → F⁻(g) is known as the A) Ionization energy B) Electron affinity C) Enthalpy of ionization D) Electronegativity E) Enthalpy of electronegativity

B) Electron affinity

Rank the following atoms in order of decreasing first ionization energies (i.e., highest to lowest): Li, Be, Ba, F. A) Ba > Li > Be > F B) F > Be > Li > Ba C) Li > Be > F > Ba D) F > Be > Ba > Li E) Ba > F > Be > Li

B) F > Be > Li > Ba

In each pair, choose the atom or ion which has the appropriate property based on its position in the Periodic Table. Greatest electron affinity

B) I

Which of the following is the correct Lewis symbol for a neutral atom of F?

B) II

Which of the following electron configurations is incorrect? A) Ca [Ar]4s² B) Mn [Ar]4s²4d⁵ C) Cu [Ar]4s¹3d¹⁰ D) Ga [Ar]4s²3d¹⁰4p¹ E) Br [Ar]4s²3d¹⁰4p⁵

B) Mn [Ar]4s²4d⁵

Which type of electromagnetic radiation has the largest wavelength? A) X-rays B) Radio waves C) Infrared D) Ultraviolet E) Microwaves

B) Radio waves

Given n = 2, identify which of the quantum numbers is NOT possible. A) l = 1 B) l = 2 C) m(l) = -1 D) m(s) = +½ E) m(s) = -½

B) l = 2

Choose the property that best predicts metallic behavior of elements in the periodic table. A) high ionization energy B) low ionization energy C) high electron affinity D) low electron affinity

B) low ionization energy

Which of the following sets of quantum numbers is not allowed? A) n = 1, ℓ = 0, mℓ = 0 B) n = 4, ℓ = 0, mℓ = -1 C) n = 3, ℓ = 1, mℓ = 0 D) n = 2, ℓ = 0, mℓ = 0 E) n = 3, ℓ = 2, mℓ = -2

B) n = 4, ℓ = 0, mℓ = -1

A lattice dissociation enthalpy (lattice energy) is A) the energy required to break a chemical bond. B) the amount of energy that must be supplied to break an ionic solid into its individual gaseous ions. C) the difference in ionization energy and electron affinity of the anion and cation. D) the energy required to convert a substance from a solid to a gaseous state.

B) the amount of energy that must be supplied to break an ionic solid into its individual gaseous ions.

Given a particular value of the principal quantum number (n), which quantum number primarily determines the shape of an orbital? A) n B) ℓ C) mℓ D) ms E) ℓm

B) ℓ

How many core electrons does an atom of beryllium (Be) contain? A) 0 B) 1 C) 2 D) 3 E) 4

C) 2

Which of the orbital electron configurations is not possible? A) 2s¹ B) 3d¹⁰ C) 4p⁷ D) 4f⁷ E) 2p⁶

C) 4p⁷

How many electrons are in the n = 2 shell in a neutral magnesium atom? A) 2 B) 6 C) 8 D) 12

C) 8

What element is designated by the orbital diagram below? A) N B) O C) F D) Ne E) Cl

C) F

Which of the following is the correct Lewis symbol for a neutral atom of Al?

C) III

Which of the following is the correct Lewis symbol for the calcium ion? A) I B) II C) III D) IV

C) III

Which element has the ground state electron configuration [Kr]5s²4d¹⁰5p³? A) Te B) Pb C) Sb D) Bi E) Sn

C) Sb

Where on the periodic table would you expect to find the most acidic elemental oxides? A) Upper left corner B) Upper right corner, including noble gases C) Upper right corner, excluding noble gases D) Lower left corner E) Lower right corner, including noble gases

C) Upper right corner, excluding noble gases

Which of the following sets of quantum numbers can describe a 3p electron? A) n = 1, ℓ = 3, mℓ = 1 B) n = 3, ℓ = 2, mℓ = 1 C) n = 3, ℓ = 1, mℓ = 1 D) n = 3 , ℓ = 0, mℓ = 1 E) n = 2, ℓ = 3, mℓ = 1

C) n = 3, ℓ = 1, mℓ = 1

If the amplitude of a electromagnetic wave increases, the wavelength will _____. A) increase B) decrease C) stay the same

C) stay the same

What is the electron configuration of Co²⁺? A) 1s²2s²2p⁶3s²3p⁶3d⁵ B) 1s²2s²2p⁶3s²3p⁶4s²3d⁵ C) 1s²2s²2p⁶3s²3p⁶4s²3d⁹ D) 1s²2s²2p⁶3s²3p⁶3d⁷ E) 1s²2s²2p⁶3s²3p⁶3d⁹

D) 1s²2s²2p⁶3s²3p⁶3d⁷

Which of the following orbitals cannot exist? A) 2p B) 3d C) 4d D) 3f E) 162p

D) 3f

Of the following, which sublevel is filled last? A) 3d B) 4s C) 4p D) 4d E) 5s

D) 4d

In a multi-electron atom, which orbital will have the highest energy? A) 4s B) 4p C) 4d D) 4f

D) 4f

How many valence electrons are in a neutral atom of nitrogen? A) 0 B) 2 C) 3 D) 5 E) 7

D) 5

How many valence electrons are in a neutral atom of chlorine? A) 0 B) 3 C) 5 D) 7 E) 17

D) 7

Which of the following is true concerning successive ionizations of an atom and its ions? A) Each successive ionization requires less energy to achieve. B) All ionizations require the same amount of energy. C) The amount of energy required to achieve a successive ionization doubles with each electron removed. D) Each successive ionization requires increasing amounts of energy. E) The first two ionizations are endothermic but each ionization afterwards is exothermic.

D) Each successive ionization requires increasing amounts of energy.

What happens to the energy of a photon if the wavelength is doubled? A) Energy doubles B) Energy quadruples C) No change in energy D) Energy is reduced by one-half E) Energy is reduced by one-quarter

D) Energy is reduced by one-half

Which of the following is not a valid Lewis symbol?

D) IV

Which of the following is the correct Lewis symbol for a neutral atom of O?

D) IV

For which one of the following is the enthalpy of the reaction the same as the enthalpy of formation? A) 2 H (g) + Se (s) → H₂Se (g) B) KOH (s) → K⁺(aq) + OH⁻ (aq) C) 2 Fe (s) + 3 Cl₂ (g) → 2 FeCl₃ (s) D) Ni (s) + ½ O₂ (g) → NiO (s)

D) Ni (s) + ½ O₂ (g) → NiO (s)

Which of the following series of isoelectronic ions (Mg²⁺, N³⁻, F⁻, Si⁴⁺) has the ionic radii in order of largest to smallest?

D) N³⁻ > F⁻ > Mg²⁺ > Si⁴⁺

Rank the following atoms in order of increasing size (i.e., smallest to largest): Li, Al, Be, Ba, O. A) Li < Al < Be < Ba < O B) Ba < Al < Li < Be < O C) Li < Be < O < Al < Ba D) O < Be < Li < Al < Ba E) O < Li < Be < Ba < Al

D) O < Be < Li < Al < Ba

Rank the following atoms in order of increasing first ionization energies (i.e., lowest to highest): Rb, F, Mg, B, N. A) F < N < B < Mg < Rb B) Rb < Mg < F < N < B C) Mg < Rb < F < N < B D) Rb < Mg < B < N < F E) Rb > B > N > F > Mg

D) Rb < Mg < B < N < F

Atomic radii decrease from left to right in a period (Na → Ar) on the periodic table. Choose the best explanation for this observed trend. A) The ionization potential decreases in that direction. B) The electron affinity increases in that direction. C) The atomic mass increases in that direction. D) The nuclear charge increases in that direction. E) The number of electrons increases in that direction.

D) The nuclear charge increases in that direction.

Energy of a photon is ______ proportional to frequency, and _______ proportional to wavelength. A) directly, directly B) inversely, inversely C) directly, not D) directly, inversely E) inversely, directly

D) directly, inversely

Red light has a _____ frequency and a _____ wavelength than ultraviolet rays. A) higher, shorter B) higher, longer C) lower, lower D) lower, longer E) lower, shorter

D) lower, longer

A single electron occupies a subshell and has the quantum numbers n = 2, ℓ = 1, mℓ = -1, ms = +½. Which of the following is an acceptable set of quantum numbers for the next electron added to this subshell? A) n = 2, ℓ = 1, mℓ = -1, ms = +½ B) n = 2, ℓ = 1, mℓ = -1, ms = -½ C) n = 3, ℓ = 0, mℓ = 0, ms = +½ D) n = 2, ℓ = 1, mℓ = 0, ms = +½ E) n = 2, ℓ = 1, mℓ = 1, ms = -½

D) n = 2, ℓ = 1, mℓ = 0, ms = +½

For an atom of carbon, which ionization will exhibit a very large increase in the energy relative to the preceding ionization? A) 1st B) 2nd C) 3rd D) 4th E) 5th

E) 5th

Which of the following elements has the smallest first ionization energy? A) S B) O C) Si D) Sr E) Cs

E) Cs

Which of the following metals would be predicted to have the smallest atomic radius? A) Cesium (Cs) B) Barium (Ba) C) Lanthanum (La) D) Europium (Eu) E) Tantalum (Ta)

E) Tantalum (Ta)

A single electron occupies a subshell and has the quantum numbers n = 3, ℓ = 0, mℓ = 0, ms = +½. Which of the following is an acceptable set of quantum numbers for the next electron added to this subshell?

E) n = 3, ℓ = 0, mℓ = 0, ms = -½

Write the condensed (noble-gas) electron configuration of Mn⁴⁺. For multi-digit superscripts or coefficients, use each number in succession.

[Ar]3d³

Write the condensed (noble-gas) electron configuration of Cu⁺. For multi-digit superscripts or coefficients, use each number in succession.

[Ar]3d¹⁰

Write the condensed (noble-gas) electron configuration of titanium. For multi-digit superscripts or coefficients, use each number in succession.

[Ar]4s²3d²

Write the condensed (noble-gas) electron configuration of copper. For multi-digit superscripts or coefficients, use each number in succession.

[Ar]4s¹3d¹⁰

Write the condensed (noble-gas) electron configuration of N. For multi-digit superscripts or coefficients, use each number in succession.

[He]2s²2p³