CM 134 General Chemistry I Exam 1, Fall 2008 Dr. Steel Name Section 1: Multiple Choice. Circle the choice that is the best answer to each question. Each question in this section is worth 2 points. 1) Choose the pure substance from the list below. A) sea water B) sugar C) air D) lemonade E) milk 2) Choose the heterogeneous mixture from the list below. A) gatorade B) chlorine gas C) black coffee D) chicken noodle soup E) carbon (graphite) 3) Choose the homogeneous mixture from the list below. A) kool-aid B)mud C)ice water D)salad dressing E) salsa 4) Molecules can be described as A) a mixture of two or more pure substances. B) a mixture of two or more elements that has a specific ratio between components. C) two or more atoms joined together in a specific geometric arrangement. D) a heterogeneous mixture E) a homogeneous mixture 5) Which of the following statements about the phases of matter is TRUE? A) In both solids and liquids, the atoms or molecules pack closely to one another. B) Solids are highly compressible. C) Gaseous substances have long-range repeating order. D) There is only one type of geometric arrangement that the atoms or molecules in any solid can adopt. E) Liquids have a large portion of empty volume between molecules. 6) Which of the following are examples of physical change? A) sugar is dissolved in water. B) coffee is brewed. C) dry ice sublimes. D) ice (solid water) melts. E) All of these are examples of physical change. 7) Which of the following are examples of a chemical change? A) coffee brewing B) water boiling C) leaves turning color in the fall D) salt dissolves in water E) None of the above are chemical changes.
8) Read the length of the metal bar with the correct number of significant figures. A) 20 cm B) 15 cm C) 15.1 cm D) 15.10 cm E) 15.100 cm 9) ow many mg does a 433 kg sample contain? A) 4.33 10-4 mg B) 4.33 10 7 mg C) 4.33 10-3 mg D) 4.33 10 6 mg E) 4.33 10 8 mg 10) All of the following are SI base units of measurement, EXCEPT A) meter B) gram C) second D) kelvin E) mole 11) Which of the following contains the FEWEST atoms? You shouldn't need to do a calculation here. A) 4.0 g Li B) 4.0 g Na C) 4.0 g Rb D) 4.0 g K E) 4.0 g Ca 12) What does "X" represent in the symbol at right? A) mercury B) chlorine C) scandium D) bromine E) selenium 13) What does "X" represent in the symbol at right? A) tin B) copper C) palladium D) niobium E) uranium 14) What species is represented by the following information? p + = 12 n = 14 e - = 12 A) Si 4+ B) Mg C) Ne D) Si E) Mg 2+ 15) What species is represented by the following information? p + = 47 n = 60 e - = 46 A) Ag + B) Nd C) Pd D) Ag E) Pd +
Section 2: Complete each question in the space provided. When possible, partial credit may be assigned if you show your work. Point values are listed after each question. 16) Calculate the atomic mass of gallium if gallium has 2 naturally occurring isotopes with the following masses and natural abundances. (5 points) Ga-69 68.9256 amu 60.11% Ga-71 70.9247 amu 39.89% 17) What is the mass of 8.49 10 24 atoms of lithium? (5 points) 18) ow many atoms of oxygen are contained in 47.6 g of Al 2 (CO 3 ) 3? The molar mass of Al 2 (CO 3 ) 3 is 233.99 g/mol. (5 points)
19) ow many significant figures are in each of the following measurements? (4 points) 1009.630 ml 3.408 10 4 m 463.090 K 0.0005890 g 20) Write the correct atomic symbol for each of the following elements. (5 points) magnesium carbon potassium iron silicon arsenic nickel calcium silver krypton 21) Complete each calculation and report your answer with the correct number of significant figures. (6 points).. (965.43 3.911) + 9413.4136..... 22) Provide the lowest, whole-number coefficients needed to properly balance each equation. A blank will be assumed to be a coefficient of 1. (5 points) Cl(aq) + Fe 2 O 3 (s) 2 O(l) + FeCl 3 (s) N 2 4 (l) N 3 (g) + N 2 (g) C 6 12 O 6 (s) + O 2 (g) CO 2 (g) + 2 O(l)
23) Determine the empirical formula for a compound that contains C, and O if it contains 52.14% C and 34.73% O by mass. (5 points) 24) An old bullet (which you suspect is lead) in the shape of a ball is found to have a mass of 10.31 grams. If the diameter of the bullet is 1.220 cm, and the formula for the volume of a sphere is, what is the density of the bullet? (5 points) 25) If the walls in a room are 955 square feet in area, and a quart of paint covers 4.0 square yards, how many gallons of paint are needed for the room? (3 ft = 1 yd, 1 gal = 4 qt) (5 points)
CM 134 General Chemistry I Exam 1, Fall 2008 Dr. Steel Name Part 3: Naming and Formulas Complete the table of names and formulas. Each blank is worth 1 point. Formula Na 2 Cr 2 O 7 SiCl 4 2 SO 3 (aq) KClO 3 Name tetrasulfur dinitride hydrochloric acid lead (IV) sulfide gallium phosphate carbonic acid N 2 O 5 aluminum cyanide Ca(NO 3 ) 2 sulfur hexafluoride CrO rubidium chloride P 2 S 7 tribromine nonafluoride SiO 2 ammonium chloride Br(aq) Bonus: Name each of these organic compounds. (2 points each) O C C C C C O O C C C