Los Angeles City College Chemistry 51 Fall 2005

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Hilary Parker
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1 Final Exam ame Part A Follow the directions and select the BEST answer for each section. Mark your answers on the scantron answer sheet carefully. Make sure your scantron answer sheet is filled out properly- do so before you begin! Clearly indicate which Scantron form is the PRIMARY and SECODARY ones by writing PRIMARY and SECODARY on the top-right hand corner of each Scantron (over your name). There are 41 questions/problems for 150 pts. total. A. Match or fill in the blank. Remember to choose the BEST answer! 3 pts. each 1. Which concept is not important when reporting a measurement? A. accuracy & precision B. scientific notation C. significant figures D. hypothesis E. appropriate measuring device 2. Which element is a transition metal? A. lead (Pb) used as radiation protection material B. mercury (Hg) used to be used in thermometers C. plutonium (Pu) a product of nuclear fission reaction D. calcium (Ca) major component of teeth E. germanium (Ge) used in the semiconductor industry for computer chips 3. Atomic clocks achieve accurate time because they are controlled by radio transmitters which themselves receive their time signals from amazingly accurate timepieces, Cesium Atomic Clocks. These clocks have an accuracy of one second in one million years! In operation, these clocks are based upon the characteristics of the cesium-133 atom, whose single electron is known to vibrate at a standard 9,162,613,770 times a second. These clocks that have an accuracy of one second in one million years! How many times does the cesium electron vibrate in one minute? A. 9,162,613,770 B x C x D x E x A form of acid rain forms when gaseous SO 2 and SO 3 react with water to form sulfurous and sulfuric acids, respectively. What are the proper chemical names for SO 2 and SO 3, respectively? A. sulfur trioxide and sulfur dioxide B. sulfur dioxide and sulfur trioxide C. monosulfur dioxide and sulfur trioxide D. sulfur dioxide and monosulfur trioxide E. sulfurous dioxide & sulfuric trioxide

2 5. Which set of values corresponds to the centigrade temperature scale for the freezing point of water, the temperature of a nice day and normal body temperature, respectively? A. 0, 77, 98.6 B. 32, 77 & 98.6 C. 273, 298 & 310 D. 0, 25 & 37 E. 32, 77 & If the smallest divisions on a thermometer are 0.01 C, you should report the temperature to the C. A. 1 B. 0.1 C D E In the periodic table, groups of elements (i.e. elements in columns) share what feature? A. similar electronegativities B. similar atomic sizes C. similar first ionization energies D. similar number of electrons E. similar number of valence electrons 8. Which class of elements is responsible for the colors of fireworks? A. solids B. noble gases C. metals D. halogens E. alkali and alkaline earth 9. Which concept best explains why you can make a highly salty cup of water, but only a slightly sweet cup of water (with sugar) at room temperature? A. opposites attract B. like dissolves like C. table salt has covalent bonds and sugar has ionic bonds D. you can make a supersaturated salt solution, but not with sugar E. none of the above 10. If you change the number of protons, neutrons and electrons, respectively, you get a different, &. A. atom, ion & isotope B. isotope, atom & ion C. atom, isotope & ion D. ion, atom & isotope E. ion, isotope & atom

3 11. Which of the following compounds is non-polar? A. CHCl 3 B. BF 4 C. H 2 C=O D. CO 2 E. H The following molecule is polar. In which direction is the dipole arrow pointing (tail to head)? A. O to S B. S to O C. O to C D. C to O E. S to C 13. How many moles of salt, acl, are required to make 1.0 liter of saline (salt in water) solution with a concentration of 0.50 moles per liter? A mol B mol C mol D. 0.5 mol E mole 14. Which of these atomic properties is not listed on a common periodic table? A. mass B. name C. symbol D. number E. they all are! 15. Which is not an intermolecular force? A. electrostatic (interaction between opposite charges) B. dipole-dipole interaction C. hydrogen bonding D. hydrophobic stacking (e.g. fat molecules solidifying into gel) E. surface tension 16. A polar head and non-polar tail comprise detergent/soap molecules. How does soap clean dirt off skin? A. it grabs the polar dirt with its tail and gets carried away by the non-polar covalent water at its head B. it grabs the non-polar covalent dirt with its tail and gets carried away by the water attracted to its head C. the charged head is attracted to the polar water molecules D. the non-polar covalent tail is attracted to the non-polar covalent dirt molecules E. like dissolves like

4 17. Oxidation is the of electrons whereas reduction is the of electrons, respectively. A. loss, loss B. loss, gain C. gain, loss D. gain, gain E. flow, flow 18. A steam burn from the condensation of 1 gram of 100 C water vapor is more damaging than a burn caused by 1 gram of 100 C boiling water because the steam. A. gives up additional energy when it condenses B. has more kinetic energy (faster moving molecules) C. both of these D. neither of these E. is less dense than liquid water 19. When salt is dissolved in water, which is the following is true? A. the melting point goes down while the boiling point goes up B. the melting point goes down while the boiling point goes down C. the melting point goes up while the boiling point goes down D. the melting point goes up while the boiling point goes up E. none of these are true 20. Which is not one of the four fundamental types of chemical reactions? A. single displacement B. double displacement C. redox D. synthesis E. decomposition 21. Fire is an example of which kind of chemical reaction? A. single displacement B. double displacement C. redox D. synthesis E. decomposition 22. The digestion of food is an example of what kind of chemical reaction? A. single displacement B. double displacement C. redox D. synthesis E. decomposition

5 23. The combustion of gasoline is an example of what kind of chemical reaction? A. single displacement B. double displacement C. redox D. synthesis E. decomposition 24. When the hydronium ion (H 3 O + ) concentration increases, what also happens? A. the [H 3 O + ] increases B. the ph decreases C. the p increases D. the [ ] decreases E. these all happen 25. In a battery which of the following is true? A. reduction occurs at the anode B. oxidation occurs at the cathode C. a light goes on when the circuit is completed D. both A & B E. neither A & B 26. What kind of material is best to use when cleaning tarnished (non-shiny) metal surface like ornaments? A. a reducing agent (substance that gets easily oxidize) B. an oxidizing agent (substance that gets easily reduced) C. another metal D. a cream E. nail polish remover 27. What can you and can you not change, respectively, when balancing a chemical equation? A. chemical formula & number of moles B. molecular formula & mole ratio C. superscripts & coefficients D. subscripts & superscripts E. subscripts & coefficients 28. A molecule containing repeating single units. A. polymer B. monomer C. carbohydrate D. peptide E. amino acid

6 29. What kind of bond exists in all proteins? A. amine/amide B. peptide/amide C. sulfide/thiol D. hydrogen E. covalent 30. Which is not an example of a natural polymer? A. hair B. wood C. nylon D. rubber E. DA 31. What is the charge of phosphorus in P 2 O 5 and HPO 4-2, respectively? A. -5 & +5 B. +5 & -5 C. +5 & +5 D. -5 & -5 E. 0 & How many bonding and non-bonding pairs of electrons are there in dihydrogen monoxide (H 2 O), respectively? A. 4 & 0 B. 3 & 1 C. 2 & 2 D. 1 & 3 E. 0 & A change alters the composition of the material and a change alters the form of the material. A. physical & physical B. physical & chemical C. chemical & physical D. chemical & chemical E. none of the above

7 PART B Solve the following problems.be sure to show all of your work if you want any credit- i.e. O WORK = O CREDIT! 33. Fill in the table below with the missing information. /6 pts. Prefix Symbol Meaning umerical Value Scientific otation nano G µ one-thousandth 1,000 1 x Fill in the ph and p values. 2 pts. ph acidic neutral basic p 35. Draw the phase diagram for water. Label its three (3) common phases - e.g. clearly indicate where they generally are found. Label the triple point. /6 pts. Pressure Temperature /14 pts. total

8 36. Draw a generic titration curve below for a diprotic base (like sulfate, SO -2 4 ) in solution titrated with a strong acid (like HCl). Label the region where each ionic species (i.e. SO -2 4, HSO - 4, & H 2 SO 4 ) exists. 5 pts. ph added acid 37. When table salt, sodium chloride (acl), dissolves in water, the ions separate from each other. Draw the individual ions of salt as they are solvated by water molecules /4 pts. 38. Draw the electron dot structure for the following polyatomic ions. /5 pts. hydronium ammonium hydroxide carbonate H 3 O + + H 4 2 CO 3 /14 pts. Total

Identify which is being oxidized and reduced by writing both of the halfreactions? H 2 + O 2 H 2 O /4 pts. oxidation: reduction: 40.

9 39. The Basilisk (aka Jesus Christ lizard- below) can escape predators by running across water. Concisely explain how it can do this. /4 pts. Balance the following reaction. Identify which is being oxidized and reduced by writing both of the halfreactions? H 2 + O 2 H 2 O /4 pts. oxidation: reduction: 40. In the diagram of the galvanic cell (battery) below, label which electrode (metal bar) is the anode and which is the cathode. Also label which side is undergoing oxidation and which side is undergoing reduction. /4 pts. /12 pts. Total

10 41. Identify the heteroatomic functional groups in the following molecules. A. putrescine (a) and cadaverine (b) have the same functional group (pg 377) /1 B. vanillin (pg 379) /3 H 2 H 3 C S C.,-diethyl-m-toluamide (DEET- an insect repellent) (pg 379) /1 O O HO D. penicillin G (pg 381) /3 O E. sucrose (pg 402) /2 HO /10 pts. Total

F. arginine (pg 414) /4 O O HO Extra credit: Give a brief example of how you can use a concept you used in this course toward your (present/future) occupation.

11 F. arginine (pg 414) /4 O O HO Extra credit: Give a brief example of how you can use a concept you used in this course toward your (present/future) occupation. Briefly the concept and how you can use it. Up to 10 pts. Double secret extra credit: (Shhhh- don t tell anyone!) What is the name of the cartoon series this book is a part of? (HIT: the author s name rhymes with complaining ) pg 7 pg 8 pg 9 pg 10 pg 11 /14 pts. total /14 pts. total /12 pts. total /10 pts. total /4 pts. total /54 pts. Total

4. Which of the following compounds is polar? A. CCl 4 B. BF 3 C. H 2 CCH 2 D. CO 2 E. NH 3 *

4. Which of the following compounds is polar? A. CCl 4 B. BF 3 C. H 2 CCH 2 D. CO 2 E. NH 3 * Exam2 Name Part A Follow the directions and select the BEST answer for each section. Mark your answers on the scantron answer sheet carefully. Make sure your scantron answer sheet is filled out properly-