CHM 134 General Chemistry I Name SOLUTIONS Exam 1, Fall 2008 Dr. Steel

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1 CHM 14 General Chemistry I Name SOLUTIONS Exam 1, Fall 2008 Dr. Steel 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) ) 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) How many mg does a 4 kg sample contain? A) 4. 10-4 mg B) 4.

2 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) cm E) cm 9) How many mg does a 4 kg sample contain? A) mg B) mg C) mg D) mg E) 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 1) 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 +

3 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 amu 60.11% Ga amu 9.89% ( amu) ( amu) = weighted amu = average mass 17) What is the mass of atoms of lithium? (5 points) 24 1mol Li atoms Li atoms Li 6.941g Li 1mol Li = 97.9 g Li 18) How many atoms of oxygen are contained in 47.6 g of Al 2 (CO )? The molar mass of Al 2 (CO ) is 2.99 g/mol. (5 points) ( CO ) 9 mol O ( CO ) 1mol Al ( CO ) 2 1mol Al atoms O 47.6 g Al2 ( CO ) = g Al 1mol O atoms O

4 19) How many significant figures are in each of the following measurements? (4 points) ml m K g 20) Write the correct atomic symbol for each of the following elements. (5 points) Mg magnesium As arsenic C carbon Ni nickel K potassium Ca calcium Fe iron Ag silver Si silicon Kr krypton 21) Complete each calculation and report your answer with the correct number of significant figures. (6 points) ( ) ) 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) 6 HCl(aq) + Fe 2 O (s) H 2 O(l) + 2 FeCl (s) N 2 H 4 (l) 4 NH (g) + N 2 (g) C 6 H 12 O 6 (s) + 6 O 2 (g) 6 CO 2 (g) + 6 H 2 O(l)

5 2) Determine the empirical formula for a compound that contains C, H and O if it contains 52.14% C and 4.7% O by mass. (5 points) Assume a 100-g sample of the compound: The formula is C 2 H 6 O % C g C 1.1 % H 1.1 g H 4.7 % O 4.7 g O 1mol C 12.01g C 1mol H g H 1mol O g O = = 2 = = 6 = = 1 24) An old bullet (which you suspect is lead) in the shape of a ball is found to have a mass of 10.1 grams. If the diameter of the bullet is cm, and the formula for the volume of a sphere is, what is the density of the bullet? (5 points) g cm ) 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? ( ft = 1 yd, 1 gal = 4 qt) (5 points) 955 ft 1 yd 1 qt 1 gal 6.6 gal ft 4.0 yd 4 qt

6 CHM 14 General Chemistry I Name SOLUTIONS Exam 1, Fall 2008 Dr. Steel Part : Naming and Formulas Complete the table of names and formulas. Each blank is worth 1 point. Formula S 4 N 2 Na 2 Cr 2 O 7 HCl(aq) SiCl 4 PbS 2 H 2 SO (aq) GaPO 4 KClO H 2 CO (aq) N 2 O 5 Al(CN) Ca(NO ) 2 SF 6 CrO RbCl P 2 S 7 Br F 9 SiO 2 NH 4 Cl HBr(aq) Name tetrasulfur dinitride sodium dichromate hydrochloric acid silicon tetrachloride lead (IV) sulfide sulfurous acid gallium phosphate potassium chlorate carbonic acid dinitrogen pentoxide aluminum cyanide calcium nitrate sulfur hexafluoride chromium (II) oxide rubidium chloride diphosphorus heptasulfide tribromine nonafluoride silicon dioxide ammonium chloride hydrobromic acid

CHM 134 General Chemistry I Exam 1, Fall 2008 Dr. Steel

CHM 134 General Chemistry I Exam 1, Fall 2008 Dr. Steel 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