CHEM 1311 Exam 1, Fall 2024 PDF

CHEM 1311: General Chemistry 1, Fall 2024 Exam #1, September 14, 2024 Class section: Instructor Section # Class time Huang 001 9:00 to 9:50 am Anka...

CHEM 1311: General Chemistry 1, Fall 2024 Exam #1, September 14, 2024 Class section: Instructor Section # Class time Huang 001 9:00 to 9:50 am Anka 002 10:00 to 10:50 am Dieckmann 003 11:00 to 11:50 am Dieckmann 004 1:00 to 1:50 pm Taylor 005 2:00 to 2:50 pm Taylor 006 3:00 to 3:50 pm TEST FORM: A You have 80 minutes to answer 28 questions AND fill out the scantron. No additional time to fill out the scantron will be given. ALL answers for grading MUST be on the front or back of the scantron. _________________________________________________________________________________ GENERAL INSTRUCTIONS: 1. For this exam, you may use any scientific or graphing calculator, as long as it is NOT capable of connecting to any online or external resource. Its memory MUST NOT contain any stored information containing content related to this course. You MAY NOT borrow another person’s calculator after exam starts. You MAY NOT use your cell phone, PDA, or other non-calculator device as a calculator. 2. Your cell phone should be turned OFF and stored in your bag or on the floor, under your seat. 3. Use ONLY a #2 pencil to fill out the scantron sheet. DO NOT use a pen or marker. 4. When filling in the bubbles on the scantron, be sure to fill in bubble completely, and ONLY ONE BUBBLE per question. Pay attention to line numbers on the scantron--put the answer in the correct spot. 5. When you first get the exam, check to make sure you have all pages of the exam, one periodic table and one useful info sheet. You should also have one scantron sheet. If you don’t have any of these, contact us immediately. 6. We will announce periodically how much time has elapsed/is remaining. 7. If you have a question, ASK! FILLING IN SCANTRON PERSONAL INFO: Bubble in the following information 1. I.D. NUMBER: your 10-digit Student ID number 2. PHONE NUMBER: 4-digit exam number in LAST 4 spots 3. TEST FORM: Test Form (A, B, C or D) (see above) 4. LAST NAME space FIRST NAME space MI (left justified) 5. SUBJ SCORE: your 3-digit section number (see above for list) GOOD LUCK! CHEM 1311: Exam #1 September 14, 2024 Page 2 of 6 QUESTIONS 1 TO 26: Multiple Choice Questions bubble appropriate answer on FRONT of scantron sheet ONE ANSWER ONLY per question __________________________________________________________________________________ 1. Which of the following sets of quantum numbers (n, l, ml, ms) could correctly describe the last electron added to a neutral potassium (Z = 19) atom in its ground state? A. 4, 3, 2, 1 B. 4, 0, 0, – ½ C. 4, 2, 1, – ½ D. 4, 4, –1, – ½ E. 4, 1, 0, + ½ __________________________________________________________________________________ 2. Which of the following transitions (in a hydrogen atom) represent emission of the longest wavelength photon? A. n = 1 to n = 3 B. n = 3 to n = 1 C. n = 4 to n = 1 D. n = 4 to n = 2 E. n = 5 to n = 4 ________________________________________________________________________________ 3. What is the mass in grams of 0.354 moles titanium (Ti)? A. 72.4 B. 0.0074 C. 16.9 D. 135 E. 7.79 __________________________________________________________________________________ 4. The number of valence electrons for Cl is________? A. 2 B. 7 C. 6 D. 5 E. 17 _______________________________________________________________________________ 5. Which of the following quantum numbers describes the difference in the orbitals shown below? A. n B. l C. ml D. ms E. l __________________________________________________________________________________ 6. An atom has a mass number of 57 and contains 31 neutrons. What is that atom? A. Ga B. Fe C. La D. F E. Ra __________________________________________________________________________________ 7. When comparing the first ionization energies (IE1) of phosphorous and sulfur, which of the following statements is correct? A. IE1(P) < IE1(S) because ionization energies generally increase from left to right in a period B. IE1(P) < IE1(S) because filled subshells provide extra stability C. IE1(S) < IE1(P) because half-filled subshells provide extra stability D. IE1(P) < IE1(S) because it is easier to add electrons as you move from left to right in a period E. IE1(S) < IE1(P) because ionization energies generally decrease from left to right in a period __________________________________________________________________________________ CHEM 1311: Exam #1 September 14, 2024 Page 3 of 6 8. Consider the following atomic symbols. Which are considered isotopes? ##! ##! ##% ##% ##% I. !"X II. !$X III. !%X IV. !"X V. !&X A. I and II only B. III, IV and V only C. II and IV only D. III and IV only E. I and IV only __________________________________________________________________________________ 9. The 2024 Paris Olympic gold medal contains only 6 grams of gold. Which of the following represents the neutral ground state electron configuration of gold(Au)? A. [Xe]6s14f145d10 B. [Xe]6s34f145d8 C. [Xe]6s14f145d96p1 D. [Xe]6s24f145d56p4 E. [Xe]6s24f145d9 __________________________________________________________________________________ 10. Which of the following is an allowed set of quantum numbers? [n, l, ml, ms] A. (3, 3, 0, +½) B. (3, 2, 1, 0) C. (3, 2, –1, +½) D. (3, 0, 1, –½) E. (3, 4, –2, –½) __________________________________________________________________________________ 11. Which of the following statements regarding the Bohr model of the atom is/are false? I. One quantum number defines each orbit. II. The electron is located in specific orbits at fixed distances from nucleus. III. The electron is treated as a particle, not a wave. IV. Each line in the emission spectrum of hydrogen is caused by an electron moving from a smaller orbit to a larger orbit. V. The Bohr model does not account for quantization of an electron’s energy. A. I, II and III only B. II and IV only C. I, IV and V only D. III and V only E. IV and V only __________________________________________________________________________________ 12. Which of the following statements is necessarily true regarding the element selenium (Se) in its neutral ground state? A. Se is diamagnetic with 16 paired valence electrons. B. Se is diamagnetic with 4 paired valence electrons. C. Se is paramagnetic with 2 unpaired valence electrons. D. Se is diamagnetic with 6 paired valence electrons. E. Se is paramagnetic with only 1 unpaired valence electron. __________________________________________________________________________________ 13. The density of platinum is 21450 kg m–3. What is that density in pg dm–3? A. 2.145 × 1019 B. 2.145 × 1013 C. 2.145 × 10–2 16 10 D. 2.145 × 10 E. 2.145 × 10 __________________________________________________________________________________ 14. Calculate DE (J) for the electron in a Bohr H atom as it transitions from n = 4 to n = 1: A. –1.36 × 10–19 J B. –2.04 × 10–18 J C. –2.18 × 10–18 J D. 2.04 × 10–18 J E. 1.36 × 10–19 J __________________________________________________________________________________ CHEM 1311: Exam #1 September 14, 2024 Page 4 of 6 15. For the element germanium (Z = 32), where do we observe the large increase (“jump”) in successive ionization energies? A. between the 5th and 6th ionization energies B. between the 2nd and 3rd ionization energies C. between the 3rd and 4th ionization energies D. between the 4th and 5th ionization energies E. between the 6th and 7th ionization energies __________________________________________________________________________________ 16. Calculate the wavelength (in nm) of the blue light emitted by a mercury lamp if its frequency is 6.88 × 1014 Hz. A. 229 nm B. 436 nm C. 206 nm D. 485 nm E. 675 nm _________________________________________________________________________________ 17. Which of the following combinations describes six (6) electrons, assuming that each contains the maximum number of electrons? A. All of the electrons in the 3d subshell B. All of the electrons in the 3d subshell with a spin of +½ C. All of the electrons in the n = 3 shell with an ml = 0 D. All of the electrons in the n = 2 shell with an ml = 1 E. All of the electrons in the n = 3 shell with a spin of +½ __________________________________________________________________________________ 18. An element has two naturally occurring isotopes. The atomic mass and percent abundance of one isotope are 106.9051 amu and 51.84%, respectively. What is the mass of the other isotope if the average atomic mass of the element is 107.8682 amu. A. 108.7629 amu B. 108.9049 amu C. 107.9672 amu D. 106.7524 amu E. 107.9888 amu __________________________________________________________________________________ 19. What element is described by the orbital diagram below? A. Ne B. B C. C D. N E. F __________________________________________________________________________________ 20. Determine the energy (J) associated with the electron in the n = 5 Bohr orbit of a hydrogen atom: A. –8.72 × 10–20 J B. –2.42 × 10–19 J C. –1.36 × 10–19 J –20 –17 D. 8.72 × 10 J E. 5.45 × 10 J __________________________________________________________________________________ CHEM 1311: Exam #1 September 14, 2024 Page 5 of 6 21. Which of the following statements is/are true about an element? I. An element is identified by its atomic number II. Isotopes of an element have the same mass in the nucleus III. Isotopes have same number of neutrons IV. Different elements cannot have the same number of protons A. I only B. I and III only C. II and IV only D. I, III and IV only E. I and IV only __________________________________________________________________________________ 22. What is the electron configuration of yttrium (Z = 39)? A. [Kr] 5s3 B. [Kr] 5s25p1 C. [Kr] 5s25d1 D. [Kr] 5s24d1 2 1 E. [Kr] 5s 3d __________________________________________________________________________________ 23. What is the mass in kg of 2.7×1026 atoms of silicon (Si)? A. 12.6 B. 0.062 C. 7.8×10–5 D. 15.96 E. 1.26×104 __________________________________________________________________________________ 24. Arrange the following elements in order of decreasing atomic radius: Rb S Ca Si Ge A. Ca > Rb > Si > Ge > S B. S > Si > Ge > Ca > Rb C. Rb > Ca > Si > Ge > S D. Si > S > Ge > Ca > Rb E. Rb > Ca > Ge > Si > S __________________________________________________________________________________ 25. The following electron configuration belongs to which group? [Ar]4s2 A. noble gases B. chalcogens C. alkali metals D. alkaline earth metals E. halogens __________________________________________________________________________________ 26. How many atoms are in 5.0×10–6 g potassium (K)? A. 8.3×10–30 B. 7.7×1016 C. 3×1018 D. 1.2×1012 E. 2.1×10–31 __________________________________________________________________________________ CONTINUE TO NEXT PAGE FOR MORE QUESTIONS CHEM 1311: Exam #1 September 14, 2024 Page 6 of 6 QUESTIONS 27 AND 28: Short Answer Questions use the BACK of the scantron sheet (lined) for these for each answer: n Number the problem n Show ALL WORK to get full credit n Print clearly (will not earn credit if we cannot easily read it) n Circle/box your final answer (if calculation) n Partial credit may be awarded for appropriate work shown (that is, your correct WORK and your ANSWER are BOTH worth part of the points….) __________________________________________________________________________________ 27. A Bohr hydrogen atom is excited and then emits light. (a) (3 pts) Calculate the change in energy (J) for the electron as it moves from the n = 7 orbit to the n = 4 orbit: (b) (3 pts) Determine the wavelength of light (nm) emitted: __________________________________________________________________________________ 28. Consider an atom of Fe (Z = 26): (a) (1 pt) Write the shorthand/abbreviated electron configuration: (b) (1 pt) How many valence electrons are in this atom? (c) (1 pt) List ALL subshells that contain the valence electrons (d) (1 pt) How many unpaired electrons are in this atom? (e) (1 pt) Indicate if the atom is paramagnetic or diamagnetic __________________________________________________________________________________ END OF QUESTIONS