HOMEWORK PROBLEMS FOR PROBLEM SESSIONS GENERAL CHEMISTRY I (Ebbing, 8 th edition) Prof. Michael A. Hauser

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1 HOMEWORK PROBLEMS FOR PROBLEM SESSIONS GENERAL CHEMISTRY I (Ebbing, 8 th edition) Prof. Michael A. Hauser Assigned homework problems are listed below. Homework problems are located at the end of each chapter. Note that each Chapter 1 problem starts with 1, Chapter 2 starts with 2, etc. These prefixes are not listed below. Note that some homework assignments include Additional Exercises written by your instructor, and these must be answered also. These will appear in the homework list as AE (for "Additional Exercise") and these problems can be found at the end of the homework list. You should work these assigned problems in the order listed in this document so that it reflects the topic order from lecture. The day prior to your scheduled Problem Session each week, you will have a general idea of which homework problems to have completed based on what topics were completed in lecture. The best approach is to work these problems in the order given until you reach a problem that we clearly have not discussed yet. Stop there. It is certainly OK to continue deeper into the list (the text reading will help), but further problems will be covered at the following week's Problem Session. The answers to the assigned problems will be discussed in Problem Session. You will not turn in your work, but your instructor will explain the grading procedure for Problem Sessions. IT IS EXTREMELY BENEFICIAL FOR YOU TO WORK ALL OF THESE PROBLEMS ON PAPER AND HAVE THEM READY FOR PROBLEM SESSION! The problems in your text are written in pairs, and the answers to the odd numbered questions appear in the Appendix. However, nearly all assigned problems are evennumbered. If you are curious whether your answers are correct for the assigned problems, you can choose to solve the odd-numbered problems to check your mastery of the material. continued on other side

2 CHAPTER a,b,c b 130 c a,c CHAPTER a,c,d b,d b,c CHAPTER 2 (cont) b,c,d CHAPTER 4 (this chapter is covered next) a,b 54 b a a AE #1 (see end of list) b,c,d 38 a,b,d AE #2 CHAPTER 3 c c 52 c CHAPTER 3 (cont) (skip "How many grams remain?" part) 102 go to Chapter 4 for CHAPTER AE #3 CHAPTER continued on next page 2

3 CHAPTER 6 (cont) CHAPTER AE # 4 82 AE #5 AE #6 AE #7 CHAPTER CHAPTER 8 (cont) a,b,c AE #8 CHAPTER 9 a 60 b,c 66 b,d a a, b (use N in center for each structure) 78 AE #9 AE # CHAPTER 9 (cont) 44 AE #11 CHAPTER a,b 34 b 36 a a a 44 (first rebuild each Lewis struc. so you can see the lone pairs on each N) AE #12 AE #13 8 AE #14 CHAPTER 11 AE #15 48 a,b (name the two transitions that occur for part "b") 12 continued on next side 3

4 CHAPTER 11 (cont) 13 a,b,d 60 AE # a AE #17 AE #18 CHAPTER a,b 26 AE # 19 AE #20 ADDITIONAL EXERCISES #1 Examine the following reactions and identify whether or not a REDOX (oxidation-reduction) reaction has occurred. If REDOX has occurred, report the following: - the atom oxidized - the atom reduced - the oxidizing agent - the reducing agent A) SiCL Mg ----> 2 MgCL 2 + Si B) SiCL H 2 O ----> 4 HCL + SiO 2 #2 Examine the reaction given below and then rewrite the statement that follows by providing the proper terms: HBr (aq) + NH 3 (l) NH 4 1+ (aq) + Br 1- (aq) The NH 3 molecule serves as a Bronsted- Lowry because it serves to a proton in the chemical reaction. #3 Based on the following balanced equation, what volume of oxygen gas would be expected from complete reaction of 27.8 grams of KCLO 3 at STP? 2 KCLO 3 (s) 2 KCL (s) + 3 O 2 (g) #4 (optional) Using the energy level postulate discovered by Bohr (E = - R H / n 2 ), calculate the energy of a hydrogen electron found in the third principal quantum level. You should look up the value of the Rydberg constant in your text. continued on next page 4

5 #5 Determine whether the following sets of quantum numbers are allowed or not allowed. If a set is not allowed, explain what is wrong with the given values. If a set is allowed, list the #-letter code for that orbital. n l m l m s a) /2 b) /2 c) /2 d) #6 What quantum number describes orbital shape? Draw a picture of an s, p, and d orbital. #7 What information does the square of the wavefunction give? #8 How many unpaired electrons are in the ground state of each of the following? a) the cobalt atom b) the tin atom c) the bromide ion #9 What is the formal charge for each atom in the following two structures? : : O : O C l O : -1 #10 Draw the Lewis Structure and give the formal charge of the central atom for the polyatomic anion PO 4-3. #11 List four ions that are isolelectronic with the element krypton. #12 For the following structure... H C C C C C H H H H H How many atoms atoms are sp 2 hybridized? How many pi (π) bonds between two carbon atoms exist in this structure? # 13 If a carbon atom is sp hybridized, what is the maximum number of π bonds that this atom could be involved in? #14 For the ion NO 2 +1 a) Draw three resonance forms (use nitrogen as central atom). b) Predict the geometry. c) Predict the hybridization of the central atom. #15 Death Valley is the lowest point in the United States (280 feet below sea level). Would you expect the atmospheric pressure in Death Valley to be greater or less than the atmospheric pressure in St. Louis? EXPLAIN how the pressure in Death Valley would affect the boiling point of a liquid. H H continued on next side 5

6 # 16 List ALL of the possible intermolecular forces possible for each of the following substances: (choose from London Dispersion, dipole-dipole, and hydrogen bonding) #20 Urea, (NH 2 ) 2 CO, is the product of protein metabolism in mammals. What is the osmotic pressure (π) of an aqueous solution containing 1.10 gram of urea [a covalent compound with formula (NH 4 ) 2 CO]) in 100. ml of solution at 20. C? a) HF b) N2 c) HCL d) Xe e) CH 3 CH 2 OH (ethyl alcohol) #17 Methyl alcohol (CH 3 OH) has a much higher boiling point than methane (CH 4 ). Use intermolecular forces to explain this large difference in boiling point. #18 Which would you expect to have the higher boiling point, carbon dioxide (CO 2 ) or acetonitrile (CH 3 CN)? The acetonitrile has the basic backbone of C - C - N; you should draw the Lewis Structure. Use intermolecular forces to explain your answer. #19 Consider the three aqueous solutions listed below: 0.10 M KBr 0.10 M CaBr M C 6 H 12 O 6 (glucose - covalent) a) Which one of these solutions would be expected to have the lowest boiling point? b) Which one of these solutions would be expected to have the lowest freezing point? 6