Chem 115 Exam I

Chem 115-M - Exam I (Test 11) - 09/25/06 Useful Information K = 273.15 + °C 1 ft³ = 28.32 L PV = nRT R = 8.206 x 10² L-atm/(mol-K) E = hv = hc/λ c = 3.00 x 10⁸ m/s 1/λ = RH(1/n₁² - 1/n₂²) 1 amu = 1.661 x 10⁻²⁷ kg ln(N₀/Nt) = kt h = 6.63 x 10⁻³⁴ J·s kt₁/₂ = ln 2 1 amu = 931.5 MeV 1 MeV = 1.602 x 10⁻¹³ J RH (Rydberg constant) = 1.096776 x 10⁷ m⁻¹ 1 J = 1 kg·m²/s² — 3. Chem 115-M Exam I (Test 11) 09/25/06 1. Which is a renewable fuel? (a) Oil (b) Pu-239 (c) Coal (d) Natural gas (e) Ethanol 2. Calewing tal mas cheris guadide required to yield 45, 4 g of mereury dID iodide using the 2 K/(00) * Hg(NO3)(e) - 2 KNO,(aq) + Hgl(s) (a) (b) (c) (d) (e) 16.6 g 31.5 g 33.2 g 46.0 g 66.3 g During the Three-mile Island incident zirconium from the fuel rods reacted with water to form hydrogen gas. ZE + 2H,0 → Z102 + 2 H2 What mass of hydrogen gas, Hy, was present if the gas had a volume of 1568 cubic feet (1 ft = 28.32 L) at a temperature of 349°C and a pressure of 50.0 atm? (a) (b) (c) (d) (e) 2.74 x 10' g H2 5.52 x 10' g H2 4.35 x 10€ g Hy 8.77 x 10' g H2 1.56 x 10 g H, 3 5. 6. 7. (a) (6) (c) (d) (e) N + 3H → NH, Ng + H2 → NH: N+ H3 → NH3 N2 + 3 H2 → 2 NH; 2N2 + 6H2 → 4 NH What is the nuclide resulting from the alpha decay of Ra-222 ? (a) (b) (c) (d) (e) Po-218 Rn-218 Fr-222 At-222 Ra-226 Control rods in a nuclear reactor work by: (a) (b) (c) (d) (e) absorbing uranium. absorbing heat from the reaction to keep it at the proper temperature. absorbing neutrons. absorbing gamma rays. maintaining the proper coolant level in the reactor. The valence electron in a sodium atom is promoted from a 3s orbital to a 3p orbital. In this process the atom: (a) (b) (c) (d) (e) undergoes B" decay. remains in the same energy state. Chem 115-M - Exam I (Test 11) - 09/25/06 For the nuclear reaction: Li + H → He + H, which of the following is true? [Li = 6.015122 amu; H = 1.008666 amu; He = 4.00260325 amu; H = 3.01604927 amu] (a) 0.513 MeV of energy is released. (b) 4.8 MeV of energy is released. (c) 6538. MeV of energy is released. (d) 4.8 MeV of energy is absorbed. (e) 7.023788 MeV of energy is absorbed. What is the half-life of an isotope if it decays to 12.5% of its radioactivity in 12 y? (a) 0.21 years (b) 4.0 years (c) 12 years (d) 8.0 years (e) 30 years How many total orbitals are available for the n = 3 energy level? (a) 5 (b) 3 (c) 9 (d) 7 (e) 11 All of the following ions have a Noble Gas electron configuration except: (a) Sr²⁺ (b) Cs⁺ (c) In (d) Te²⁻ (e) I⁻ We know that the energies of electrons in atoms are quantized because: (a) atoms absorb light as they are excited. (b) atomic spectra are line spectra. (c) the energy of the lines in atomic spectra are much less than the energies of gamma-rays. (d) at most only two electrons can occupy a single orbital. (e) electrons occupy discrete orbitals. Question 13: Which lists the elements in order of increasing size? (a) Al < In < S (b) In < Al < S (c) S < Al < In (d) Al < S < In (e) S < In < Al Question 14: The counts from a sample containing a radioactive nuclide drop from 876 counts per second to 544 counts per second in 3.000 days (2.592 x 10⁵ seconds). What is the half-life of the nuclide in seconds?   (a) 1.84 x 10⁻⁶ seconds (b) 6.21 x 10⁻⁶ seconds (c) 1.12 x 10⁵ seconds (d) 3.77 x 10⁵ seconds (e) 8.68 x 10⁵ seconds Question 15: A metastable isotope of lead results from the decay of bismuth. The metastable lead then decays via emission of a gamma ray, as follows:   ²⁰⁷mPb → ²⁰⁷Pb + γ The ²⁰⁷Pb nuclide has a mass of 206.975885 amu. The emitted gamma ray has an energy of 1.63 MeV. Which statement describes the mass of the metastable nuclide? (a) The mass of ²⁰⁷mPb is greater than ²⁰⁷Pb by 1.75 x 10⁻³ amu. (b) The mass of ²⁰⁷mPb is greater than ²⁰⁷Pb by 1.51 x 10⁻³ amu. (c) The mass of ²⁰⁷mPb is greater than ²⁰⁷Pb by 571 amu. (d) The mass of ²⁰⁷mPb is less than ²⁰⁷Pb by 1.75 x 10⁻³ amu. (e) The mass of ²⁰⁷mPb is less than ²⁰⁷Pb by 571 amu. Chem 115-M - Exam I (Test 11) - 09/25/06 Question 16: Text: Calculate the binding energy per nucleon of nitrogen-14. Atomic masses for nitrogen-14, hydrogen-1, and neutron. Answer choices (a) to (e). Question 17: Text: A portion of the emission spectrum of hydrogen is shown. An image of a portion of the hydrogen emission spectrum. Textual Content: Question 16: Calculate the binding energy per nucleon of nitrogen-14. [¹⁴₇N = 14.003075 amu; ¹₁H = 1.00783 amu; ¹₀n = 1.008666 amu] Answer Choices: (a) 1.42 x 10¹¹ kJ/(mole nucleons) (b) 1.01 x 10¹⁰ kJ/(mole nucleons) (c) 1.45 x 10¹⁰ kJ/(mole nucleons) (d) 2.79 x 10⁻³⁸ kJ/nucleon (e) 1.20 x 10⁻¹⁵ kJ/nucleon Question 17: A portion of the emission spectrum of hydrogen is shown. Chem 115-M - Exam I (Test 11) - 09/25/06 Question 17: Text: If the lines shown result from transitions to the n = 3 level, lines I and II correspond to which transitions? Answer choices (a) to (e) with corresponding transitions. Question 18: Text: Which of the following could contain the SO₄²⁻ anion? Answer choices (a) to (e) with chemical formulas. Textual Content: Question 17: If the lines shown result from transitions to the n = 3 level, lines I and II correspond to which transitions? (a) I: n = 3 to n = 2, II: n = 3 to n = 1 (b) I: n = 5 to n = 3, II: n = 4 to n = 3 (c) I: n = 3 to n = 5, II: n = 3 to n = 4 (d) I: n = 4 to n = 3, II: n = 5 to n = 3 (e) I: n = 5, II: n = 4   Question 18: Which of the following could contain the SO₄²⁻ anion? (a) MgSO₄ (b) Ca₂SO₄ (c) Na(SO₄)₂ (d) SO₄Cl₂ (e) C(SO₄)₄ Chem 115-M - Exam I (Test 11) - 09/25/06 Question 19: Text: Which is the correct electron configuration for Ca in its ground state? Answer choices (a) to (e) with electron configurations and arrows indicating electron placement. Question 20: Text: Which exhibits both ionic and covalent bonding? Answer choices (a) to (e) with chemical formulas. Footer: END OF EXAM, instructions for filling out the scan sheet, and information about answer posting. Textual Content: Question 19: Which is the correct electron configuration for Ca in its ground state? (a) 1s²2s²2p⁶3s²3p⁶3d² with 3d filled as ↑↑↓ ↓ ↓ ↓ (b) 1s²2s²2p⁶3s²3p⁶3d² with 3d filled as ↑↓ ↑↓ ↑↓ (c) 1s²2s²2p⁶3s²3p⁶4s² with 4s filled as ↑↑ (d) 1s²2s²2p⁶3s²3p⁶4s² with 4s filled as ↑↓ (e) 1s²2s²2p⁶3s²3p⁶4s¹3d¹ in order to achieve a half-filled s-orbital Question 20: Which exhibits both ionic and covalent bonding? (a) Na₂S (b) LiI (c) CH₂Cl₂ (d) SO₃NH₃ (e) Cs₃PO₄ Footer: END OF EXAM Instructions for filling out the scan sheet, including name, PUID number, section number, and test number. Information about answer posting on the CHM 115 website.