<p>Chem 1102 Exam 1B February 8, 2006 15 points</p><p>Name______Section______</p><p>I. (24) Multiple Choice (12 questions @ 2 points). Circle correct answer on exam and mark correct answer on Scantron. Put your name and section number on Scantron.</p><p>1. Reaction with oxygen includes</p><p>1. decomposition 2. sublimation **3. Combustion compound + O2  CO2 and H2O **4. Metabolism food + O2  CO2 and H2O</p><p>A. 1, 3 and 4 B. 2 and 3 **C. 3 and 4 D. 1 only</p><p>2. Which statement is true for compounds? Sec 1.6-1.7</p><p>A. Compounds can be separated into constituent atoms by physical means. **B. Compounds consist of two or more atoms chemically bonded together. C. A compound is a heterogeneous mixture. D. The elements in a compound are not in a fixed ratio.</p><p>3. Three molecules of calcium phosphate, Mg3(PO4)2 have </p><p>A. 8 O atoms B. 2 P atoms C. 6 Mg atoms **D. 24 O atoms Each molecule has 8 O atoms so 3 molecules have 24 O </p><p>4. Atrazine is a common pesticide. The maximum contaminant level in U.S. lakes is 0.003 ppm. What is the value of this concentration in scientific notation?</p><p>**A. 3E-9 0.003 ppm = .003/1E+6 = 3E-9 B. 3E-7 C. 3E-5 D. 3E-3</p><p>1 5. All isotopes of uranium have</p><p>A. 238 protons B. 238 electrons **C. 92 protons U has Z = 92 = # protons D. 92 neutrons</p><p>6. Chlorine gas was the first chemical weapon. It can lead to immediate death because it</p><p>**A. produces acid with water. B. causes cancer. C. causes heart attacks. D. binds with hemoglobin more strongly than oxygen. </p><p>7. An example of ______is when sugar dissolves in water, </p><p>**A. a physical process B. a chemical process C. combustion D. melting</p><p>8. Salt is spread on road ice and antifreeze is added to a car radiator because they </p><p>A. raise the freezing point of water B. lower the boiling point of water C. cause a chemical reaction with water **D. lower the freezing point of water </p><p>9. The chemical reaction for one atom of elemental carbon reacting with one molecule of gaseous water to produce one molecule of gaseous carbon monoxide and one molecule of gaseous elemental hydrogen is</p><p>A. C (s) + H2O(g)  CO(g) + 2H(g) **B. C(s) + H2O(g)  CO(g) + H2(g) C. C(s) + 2H2O(g)  CO2(g) + 2H2(g) D. C2(s) + H2O(g)  C2O(g) + H2(g)</p><p>10. The electrons in an atom that participate in chemical bonding are called</p><p>A. an octet of electrons B. radioactive **C. valence electrons D. ions</p><p>2 11. Studies of the “antifreeze” protein in snow fleas and hibernation may lead to improvements in</p><p>**A. organ transplant B. energy conservation C. protection against chemical warfare D. healing of broken bones</p><p>12. A new element with Z = 113 is called Un and is predicted to **1. form UnCl3 2. form NaUn 3. be a nonmetal **4. be a metal 5. give up one electron</p><p>A. 1, 3 and 5 B. 2 and 3 C. 1 only **D. 1 and 4 Un is in Group IIIA and is like Al</p><p>II. (17) Short Answers</p><p>1. Fluorine, F, has one bonding and ____6__ nonbonding electrons.</p><p>2. The readout of your calculator, digital clock or CD player consists of molecules called __liquid crystals______.</p><p>3. (4) An unknown substance has these properties  Freezing Point = -5.7 oC  Boiling Point = 125 oC.  It does not conduct electricity.  When it burns in oxygen, the only products are carbon dioxide and water.</p><p>True or False?</p><p>__T___a. At - 25 oC, this substance is a solid.</p><p>___F__b. When burned, one molecule of the substance produces 3 molecules of carbon dioxide. Then, each molecule of the unknown has 6 carbon atoms.</p><p>4. (3) The symbol 59Co has _27___ protons, __27___ electrons and ____32_ neutrons. Co has Z = 27 = # protons and + electrons. It also has (59-27) = 32 neutrons.</p><p>5. A Group VIIA element has __7____ valence electrons and is a [metal, nonmetal, metalloid].</p><p>3 6. Density has units of _ mass/volume, g/mL, kg/L, etc__. (several answers are possible)</p><p>7. The forces that prevent electrons from flying off an atom and the forces that cause chemical bonding are called __electrostatic______forces.</p><p>III. (9) Problems</p><p>1. (4) In the Super Bowl game, a Pittsburgh Steeler player ran 75 yards. How many km is this distance? Express your answer in scientific notation. [1 yd = 3 ft, 1 ft = 12 in, 1 in = 2.54 cm]</p><p>75 yd x (3 ft/1 yd) x (12 in/1 ft) x (2.54 cm/1 in) x (1 m/100 cm) x (1 km/1000 m) = 6.86E-2 km</p><p>2. (3) Balance this chemical equation</p><p>_2____Al + __6___HCl  __2___AlCl3 + __3___H2</p><p>3. (2) Use the shorthand notation 2, 8, 18 for the electron shells to write the shorthand notation for the electron configuration in S? S has 16 electrons so the shorthand notation is 2, 8, 6</p><p>Extra Credit: How many μg are there in 2.54 pounds? (1 lb = 454 g)</p><p>2.54 lb x (454 g/1 lb) x (1 μg/1E-6 g) = 1.15E+9 μg</p><p>4</p>