chem1a-spring04-mt2-unknown-exam - Sample Midterm 2 Exam...

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Unformatted text preview: Sample Midterm 2 Exam Part 1: Multiple Choice. (5 pts each, 40 pts total) Instructions: Bubble in the correct answer on your Scantron™ form AND circle the answer on your exam. Each question has one correct answer. 1.) The answer to question 1 is A. Bubble in A on your Scantron™ form. 2.) To which orbital does the plot of |ψ|2 vs φ correspond? A.) 1s B.) 2s C.) 2px D.) 2py E.) 2pz 2 |ψ | 0 0 3.) B.) H (2s) C.) H (4s) D.) He+ (4s) E.) He+ (8s) Identify the atom or ion with the electronic configuration [Ne]3s3p6? A.) Ar+ 5.) 2π The ionization of which with UV light at 90 nm will produce electrons with the longest de Broglie wavelength? A.) H (1s) 4.) φ B.) K+ C.) Ar D.) K E.) Cl– Which has the largest atomic or ionic radius? A.) Ar+ B.) K+ C.) Ar D.) K E.) Cl– Page 2 of 4 6.) Which is the most electronegative? A.) H 7.) Name: _________________________________________ B.) Na C.) K D.) Cl E.) Br Which is not paramagnetic in its ground state? σ* 2pz π* 2p A.) O B.) O– C.) O2– D.) O2 E.) O2– π2p σ2p z σ* 2s σ2s O2 8.) After diving, which ascent poses the gravest danger to a diver holding his or her breath? 1 atm A.) 10m→0m B.) 20m→10m D.) 60m→30m C.) 40m→20m E.) 100m→40m water 10 m The atoms or molecules of which ideal gas have the greatest average kinetic energy? A.) Ar at 200 °C B.) He at 400 °C D.) H2 at 200 °C C.) He at 100 °C E.) H2 at 100 °C 10 m 2 atm 3 atm 9.) air Page 3 of 4 Name: _________________________________________ Part 2: Short Answer Problems (105 pts total) Instructions: Enter answers in the boxes provided. Show your work and justify your answer. (25 pts) 1.) Consider the H atom and He+ ion. a) What is the maximum wavelength of light that will ionize H(2s)? Answer: b) Light of what wavelength will induce the n=4 → n=8 transition in He+? Answer: (30 pts) 2.) Consider an atom of the element aluminum (Al) in its ground state. a) Write the electron configuration for an atom of Al. Answer: b) Write down the values of the quantum numbers for an electron in the highest occupied orbital. n: ml: c) l: ms: Sketch the highest occupied atomic orbital and indicate number and type of nodes. Answer: Page 4 of 4 Name: _________________________________________ (25 pts) 3.) Consider 4.4 g of a hydrocarbon (hc) gas with the empirical formula C3H8. a) The hydrocarbon fills a balloon to 0.56 L at 4.4 atm and 300 K. What is the molecular formula of the hydrocarbon? Answer: b) Shown is a plot of the molecular speed distribution, F(v), and vrms for CO2 at 300 K. Sketch F(v) and indicate vrms for the hydrocarbon gas at 300 K and 600 K. vrms 0.0025 F(v) 0.0000 0.0025 0.0025 F(v) F(v) 0 500 1000 1500 2000 v (m/s) hc at 600 K hc at 300 K CO2 at 300 K 0.0000 0 500 1000 1500 2000 v (m/s) 0.0000 0 500 1000 1500 2000 v (m/s) (25 pts) 4.) Two sunscreen products (X and Y) have the following extinction coefficients, ε, at 310 nm: X = 3.0 cm2/g and Y = 1.0 cm2/g. For the following questions, the absorbance should be calculated for a 1 cm sample path length. a) What is the absorbance of a 0.1 g/mL sample of X? Answer: b) A 0.10 g/mL sample of either X or Y is placed in the spectrometer. The measured ratio of the intensity of the transmitted light to the intensity of the incident light is 0.80 at 310 nm. Is the sample sunscreen X or Y? Answer: ...
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This note was uploaded on 02/08/2010 for the course CHEM 1A taught by Professor Nitsche during the Spring '08 term at University of California, Berkeley.

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