Chemistry 103 Practice Exam - W&M

PRACTICE EXAM CHEM 103 Name Sections 1 & 2 Semester exam 1 PRACTICE EXAM September 27, 2024 W&M ID Number By affixing my name above I agree to the W&M honor pledge: “I pledge on my honor not to lie, cheat, or steal, either in my academi...

PRACTICE EXAM CHEM 103 Name Sections 1 & 2 Semester exam 1 PRACTICE EXAM September 27, 2024 W&M ID Number By affixing my name above I agree to the W&M honor pledge: “I pledge on my honor not to lie, cheat, or steal, either in my academic or personal life.” Please write your name on the first page and your student id number on EACH page. Please show all work so that maximum partial credit may be awarded. Good Luck! ℎ𝑐𝑐 1 Equations 𝑍𝑍 2 𝑍𝑍 2 𝑐𝑐 = 𝜆𝜆𝜆𝜆 𝐸𝐸 = ℎ𝜈𝜈 = = 𝑚𝑚v 2 ∆𝐸𝐸 = (−2.178 × 10−18 J) 2 − 2 𝜆𝜆 2 𝑛𝑛𝑓𝑓 𝑛𝑛𝑖𝑖 2 2 ℎ 𝐶𝐶𝑍𝑍 + 𝑍𝑍 − 1 𝑍𝑍 𝑍𝑍 𝜆𝜆 = 𝐸𝐸lattice = = 𝑅𝑅∞ 2 − 2 ; 𝑅𝑅∞ = 1.097 × 107 m–1 𝑚𝑚v 𝑅𝑅0 𝜆𝜆 𝑛𝑛𝑓𝑓 𝑛𝑛𝑖𝑖 Constants and Conversion Factors m 8 m2 𝑐𝑐 = 2.998 × 10 1 J = 1 kg s s2 −34 electron mass = 9.11 × 10−31 kg ℎ = 6.626 × 10 J∙s electron charge = −1.602 × 10−19 C K = 273.15 + ℃ 1 u (or amu) = 1.661 × 10−27 kg 𝑁𝑁𝐴𝐴 = 6.022 × 1023 mol−1 1 L = 1000 cm3 PRACTICE EXAM Short answer questions, etc... 1. (10 pts) Fill in the blanks with the correct answers. a. ________ is the symbol for the element with 33 protons. b. The isotope Am-241 has __________ neutrons. c. The usual charge of Cs ion is ________. d. By assuming the usual charge in part c, the Cs ion has the same number of electrons as the neutral atom __________ (give the symbol). e. Both cesium ion and the neutral atom from part d have 6 electrons in their s p d f (circle one) outermost subshell. 2. (9 pts) Sketch pictures of a 1s orbital, a 2p orbital and a 3d orbital, indicating all nodal planes. 3. (8 pts) Fill in the COMPLETE electron configuration for the Fe4+ ion. 1s2 2s2 ______________________________________________________ PRACTICE EXAM Numerical Problems. Show your reasoning clearly and show all your work 4. (7 pts) Carat weight in diamonds is defined as follows: 1.000 gram = 4.878 carats. How many carbon atoms are there in a 10.4 carat diamond? 5. (10 pts) In the opening scene of the film Raiders of Lost Ark, Indiana Jones tries to remove a gold idol from a booby-trapped pedestal. He replaces the idol with a bag of sand of approximately equal volume. The density of gold = 19.32 g/cm3 and the density of sand = 2.05 g/cm3. Assuming that the idol measured 5.0 × 6.0 × 8.5 cm, what volume of sand (in cm3) would REALLY have been needed to equal the mass of the gold idol? PRACTICE EXAM 6. (10 pts) Despite its status as a noble gas, xenon (Xe) can form a few compounds. 1.00 g of Xe is found to combine with 0.579 g of F2 to make compound A or with 0.868 g of F2 to make compound B. What are likely formulas for compounds A and B? 7. (12 pts) There are three naturally-occurring isotopes of silicon. Using the data provided below, calculate the weighted average atomic mass for silicon. You MUST show calculation work to receive credit for this problem. isotope exact mass natural abundance 28 Si 27.97693 amu 92.2093 % 29 Si 28.97649 amu 4.7012 % 30 Si 29.97376 amu 3.0895 % PRACTICE EXAM 8. (10 points) A Li2+ ion (Z=3) is excited in an electrical discharge. An excited electron in level n=5 makes a transition to n=4. What is the wavelength of the photon that is emitted (in nm units)? PRACTICE EXAM Multiple Choice. (24 pts) In the blank at left write in the letter of the one choice that best answers the question or completes the statement. Respond to every question. There is no penalty for guessing. 4 points each. 9. The energy carried by photons is most directly associated with which property? a) Frequency b) Mass c) Velocity d) Amplitude e) Spin 10. The number of unpaired electrons in the Co3+ ion is a) 0 b) 1 c) 2 d) 3 e) 4 f) 5 11. Which of the following is a heterogeneous mixture? a) A solution of NaCl in water b) A sheet of window glass c) A sample of air d) A sample of muddy pond water e) A sample of dry ice (solid CO2) 12. How many nanometers are in 3.0 millimeters? a) 3000 b) 3 × 106 c) 3 × 109 d) 3 ×10–6 e) 3 × 10–9 13. Which of these numbers is the largest? a) The number of protons in N b) The number of neutrons in 19F c) The number of electrons in O d) The number of neutrons in 13C e) The number of 3d electrons in Ni 14. A Denny’s Grand Slam® breakfast contains 2 eggs, 3 slices of bacon, and 4 pancakes. If I ordered 1 mole of grand slam breakfasts, how many slice of bacon would I receive? Mmm… Bacon! a) 3 × 1023 b) 6 × 1023 c) 9 × 1023 d) 12 × 1023 e) 18 × 1023