Lab Day and Time: Instructions. 1. Do not open the exam until you are told to start.

Transcription

1 Name: Lab Day and Time: Instructions 1. Do not open the exam until you are told to start. 2. This exam is closed note and closed book. You are not allowed to use any outside material while taking this exam. 3. Use the spaces provided to write down your answers. To receive full credit, you must show all work. Do not write answers on any other pieces of paper. If you need more room, write on the back of the exam and be sure to include a note describing where the work is located. 4. When solving numerical problems, make sure you include the proper units in your final answer. 5. If a question asks for a response in sentence or paragraph form, make sure you respond in that format. 6. Useful data for the exam and a periodic table are provided on the last page of the exam. Carefully tear out these sheets if you wish. Page # Points possible Points awarded Attendance 3 EC 2 Total 100 1

2 Multiple Choice Unless otherwise directed, choose the single best answer for each question. Please use the space provided to do your calculations. 1. How many significant figures should be in the answer to the calculation shown below? a. 1 b. 2 c. 3 d. 4 e According to our discussion in class, what is the simplest stable building block of matter? a. molecule d. neutron b. proton e. atom c. electron 3. I was asked to report the mass of a sample of water in the proper SI units. What should the units be? a. g d. mg b. kg e. None of the above c. mole 4. Convert 89.3 nl to kl. a. 8.93x10-11 kl b. 8.93x10-8 kl c. 8.93x10 7 kl d. 8.93x10 10 kl 5. The element in the upper right corner of the periodic table. a. is a metal b. is a metalloid c. is an alkali metal d. is a halogen e. is a noble gas 2

3 6. Which of the following elements has physical and chemical properties most similar to Chlorine? a. H d. S b. Ne e. Br c. Na 7. How many total atoms are indicated by the formula and coefficient written below? 3 CHCl 3 a. 3 d. 15 b. 5 c Express in the proper form of scientific notation. a. 3x10 5 b x10-5 c x10 1 d x10 5 e. None of the above 9. How many significant figures are in the measurement below? cm a. 2 d. 5 b. 3 e. 6 c How many significant figures should be in the answer to the calculation shown below? a. 1 b. 2 c. 3 d. 4 e

4 11. The output of a German precision ball bearing plant is x10 6 g of ball bearings per five days. If each ball bearing has a mass of g, how many ball bearings does the plant make in a single day? a. 3.84x10 5 ball bearings b. 7.67x10 4 ball bearings c. 867 ball bearings d. 3.48x10 7 ball bearings 12. How many significant figures should be in the answer to the calculation shown below? a. 1 d. 4 b. 2 e. 5 c What element has 25 neutrons and a mass number equal to 47? a. Mn b. Ag c. Hf d. Ti 14. Which of the following elements is an alkaline earth metal? a. Sc b. Cu c, Al d. Na e. None of the above is an alkaline earth metal. 15. According to our discussion in class, we use the scientific method to help us study/understand chemistry. What is the first step when using the scientific method? a. Generate a hypothesis. b. Develop a theory. c. Make an observation. d. Perform an experiment. 4

5 Use the diagrams below to answer questions 16 through 18. In the diagrams, assume each ball represents a different element. The transition from box A to box B represents a sample of matter that has undergone a change. A B 16. Under normal conditions (i.e. the temperature and pressure of the classroom right now), a sample of matter is best represented by box B. How do the attractive forces of the particles contained in this sample of matter compare to those of water particles under the same conditions? a. They are stronger than those of water particles. b. They are weaker than those of water particles. c. They are similar in strength to those of water particles. 17. When the transition from box A to box B occurs, what happens? a. A physical change. b. A chemical change. c. A chemical and physical change. 18. According to our discussion in class, what type of matter is represented by diagram A? a. pure element d. heterogeneous mixture b. pure compound c. homogeneous mixture 19. A sample of matter has a density equal to 1.11 g/ml. What is the volume of a 3.00x10 7 µg sample of this matter? a ml b ml c ml d ml 5

6 20. Fill in the missing information into the table. (10 points) Element Name Element Symbol Sb Cadmium Sn Silver Argon 21. What is the absolute uncertainty of the number written below? (3 points) 1060 kl 22. An atom forms a 2+ ion. If the ion has 38 electrons, what is the chemical symbol of the ion? (2 points) If the mass number of the ion is equal to 78, what is the elemental notation for the ion? (2 points) 23. On the left hand side of the arrow below, draw a picture of the potassium (K) atom. Assume the potassium has 18 neutrons. On the right hand side of the arrow, draw a picture of the ion that potassium forms. In your diagrams, include the location and number of the protons, neutrons, and electrons. Label the nucleus and make sure the relative sizes of the atom and ion are accurate. Underneath the ion, label it as a cation or anion. (6 points) 6

7 24. In order to receive full credit for the questions below, you must show all of your work and use a vertical dashed line to show where the significant figures end in all calculated values. You must show a rounded and unrounded value for each answer and place a box around the final answers for each part. While working in my backyard this weekend I found a meteorite! My chemist friends and I dropped everything and did some chemical analyses. One of the things we found was that the meteorite was composed of a pure element. In order to help us identify the composition of the meteorite, we tried to experimentally determine its density. When the meteorite was placed in x10-3 m 3 of water contained in a graduated cylinder, the water level rose to a volume of 1.862x10-3 m 3. a.) What was the volume of the rock in m 3? Make sure your answer is in the proper form of scientific notation. (4 points) b.) What is the volume of the meteorite in ml? You must show all work and use dimensional analysis to receive full credit. (5 points) c.) If the meteorite has a mass of 3.083x10-1 tons, what is the mass in grams? You must show all work and use dimensional analysis to receive full credit. Express your answer in the proper form of scientific notation. (4 points) d.) What is the density of the meteorite in g/ml? (2 points) e.) Besides the fact that we found a meteorite, based on the information given and calculated above, why should we be excited about our discovery? (2 points) 7

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9 Conversion Factors, Constants, and Periodic Table 1 m = yards (symbol for yard is yd) 1 inch = 2.54 centimeters (exact) 12 inches = 1 ft (exact) 1 gallon = liters 1 mile = feet 1 pound = grams 1 ton = 2000 pounds (exact) 1 fl oz. = ml 1 dollar = 4 quarters (exact) 1 H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc (98) 44 Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po (209) 85 At (210) 86 Rn (222) 87 Fr (223) 88 Ra Ac Rf (261) 105 Db (262) 106 Sg (263) 107 Bh (262) 108 Hs (265) 109 Mt (266) 110 Uun (269) 111 Uuu (272) 112 Uub (277) Ce Pr Nd Pm (145) 62 Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np (237) 94 Pu (244) 95 Am (243) 96 Cm (247) 97 Bk (247) 98 Cf (251) 99 Es (252) 100 Fm (257) 101 Md (258) 102 No (259) 103 Lr (260) 9