CHM2045 F13: Exam #3 2013.11.15 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A metal crystallizes in a face centered cubic structure and has a density of 11.9 g/cm 3. If the radius of the metal atom is 138 pm, what is the identity of the metal? A) Cr B) Mn C) At D) Pd E) Fe 2) One significant difference between gases and liquids is that. A) a gas may consist of both elements and compounds B) a gas assumes the volume of its container C) a gas is made up of molecules D) gases are always mixtures E) All of the above answers are correct. 3) How many moles of gas are there in a 45.0 L container at 25.0 C and 500.0 mm Hg? A) 18.4 B) 0.630 C) 207 D) 6.11 E) 1.21 4) Why is water an extraordinary substance? A) Water has an exceptionally high specific heat capacity. B) Water is the main solvent within living organisms. C) Water has strong hydrogen bonding. D) Water has a low molar mass, yet it is a liquid at room temperature. E) All of the above. 5) Which of the following is not equivalent to 1 atm pressure? A) 10 cm Hg B) 101 kpa C) 14.7 lb/in2 D) 760 mm Hg 6) What is the strongest type of intermolecular force present in NH 2 CH 3? A) hydrogen bonding B) ion-dipole C) dipole-dipole D) dispersion E) none of the above 7) How much energy is required to vaporize 48.7 g of dichloromethane (CH 2 Cl 2 ) at its boiling point, if its H vap is 31.6 kj/mol? A) 18.1 kj B) 55.1 kj C) 6.49 kj D) 15.4 kj E) 31.2 kj 8) Ammonium nitrite undergoes thermal decomposition to produce only gases: NH4NO2 (s) N 2 (g) + 2H2O (g) What volume (L) of gas is produced by the decomposition of 35.0 g of NH4NO2 (s) at 525 C and 1.5 atm? A) 47 B) 24 C) 15 D) 72 E) 160 A-1
9) Calcium hydride (CaH2) reacts with water to form hydrogen gas: CaH2 (s) + 2H2O (l) Ca(OH)2 (aq) + 2H2 (g) How many grams of CaH2 are needed to generate 48.0 L of H2 gas at a pressure of 0.888 atm and a temperature of 32 C? A) 50.7 B) 0.851 C) 71.7 D) 143 E) 35.8 10) Identify the type of solid for diamond. A) molecular solid B) nonbonding atomic solid C) networking atomic solid D) ionic solid E) metallic atomic solid 11) Identify the term used to describe the ability of a liquid to flow against gravity up a narrow tube. A) surface tension B) capillary action C) density D) viscosity E) none of the above 12) The density (in g/l) of CO 2 at 1140 torr and 60.0 C is. A) 44.0 B) 10.9 C) 5.70 D) 16.2 E) 2.42 13) Which of the following phase transitions indicates deposition? A) liquid solid B) gas solid C) liquid gas D) solid gas E) solid liquid 14) Mercury is toxic and a liquid at room temerature. If merury be spilled on the floor, typically the builiding is evacuated util the mercury spill has been cleaned up. What term below describes why the liquid mercury is a danger to the building's inhabitants? A) Viscosity B) van der Waals forces C) Surface tension D) Vapor pressure E) Capillary action 15) A sample of an unknown volatile liquid was injected into a flask (mflask = 27.0928 g, Vflask = 0.1040 L) and heated until no visible traces of the liquid could be found. The flask and its contents were then rapidly cooled and reweighed (mflask+vapor = 27.4593 g). The atmospheric pressure and temperature during the experiment were 0.976 atm and 18.0 C, respectively. The unknown volatile liquid was. A) C7H16 B) C7H14 C) C6H6 D) C6H14 E) C6H12 A-2
16) 10.0 grams of argon and 20.0 grams of neon are placed in a 1200.0 ml container at 25.0 C. The partial pressure of neon is atm. A) 8.70 B) 20.2 C) 3.40 D) 0.700 E) 5.60 17) Vanadium crystallizes in a body centered cubic structure and has an atomic radius of 131 pm. Determine the density of vanadium, if the edge length of a bcc structure is 4r/ 3. A) 3.06 g/cm 3 B) 12.2 g/cm 3 C) 8.46 g/cm 3 D) 6.11 g/cm 3 E) 2.77 g/cm 3 18) Consider the phase diagram below. If the dashed line at 1 atm of pressure is followed from 100 to 500 C, what phase changes will occur (in order of increasing temperature)? A) fusion, followed by vaporization B) condensation, followed by vaporization C) vaporization, followed by deposition D) sublimation, followed by deposition E) No phase change will occur under the conditions specified. 19) Which of the following is not a type of solid? ionic molecular supercritical metallic covalent-network A) molecular B) covalent-network C) supercritical D) metallic E) ionic A-3
20) A real gas will behave most like an ideal gas under conditions of. A) high temperature and low pressure B) low temperature and low pressure C) high temperature and high pressure D) low temperature and high pressure E) strong intermolecular forces 21) Consider the phase diagram shown. Choose the statement below that is TRUE. A) The solid phase of this substance is higher in density than the liquid phase. B) The line separating the solid and liquid phases represents the H vap. C) The triple point of this substance occurs at a temperature of 31 C. D) At 10 atm of pressure, there is no temperature where the liquid phase of this substance would exist. E) None of the above are true. 22) Which is the smallest quantity of pressure? A) 1 centimeter of Hg B) 1 atm C) 1 mm Hg D) 1 pascal 23) NaCl crystallizes in a cubic unit cell with Cl- ions on each corner and each face. How many Na+ and Cl - ions are in each unit cell of NaCl? A) 8 Na+ ions and 8 Cl- ions B) 4 Na+ ions and 4 Cl- ions C) 1 Na+ ion and 1 Cl- ion D) 2 Na+ ions and 2 Cl- ions A-4
24) Place the following substances in order of decreasing boiling point. H 2 O N 2 CO A) CO > N 2 > H 2 O B) CO > H 2 O > N 2 C) N 2 > CO > H 2 O D) N 2 > H 2 O > CO E) H 2 O > CO > N 2 25) The volume of an ideal gas is zero at. A) -45 F B) -273 C C) 0 C D) -273 K E) -363 K 26) Place the following compounds in order of increasing strength of intermolecular forces. CH 4 CH 3 CH 2 CH 3 CH 3 CH 3 A) CH 4 < CH 3 CH 3 < CH 3 CH 2 CH 3 B) CH 3 CH 2 CH 3 < CH 4 < CH 3 CH 3 C) CH 3 CH 3 < CH 4 < CH 3 CH 2 CH 3 D) CH 3 CH 2 CH 3 < CH 3 CH 3 < CH 4 E) CH 4 < CH 3 CH 2 CH 3 < CH 3 CH 3 27) According to kinetic-molecular theory, in which of the following gases will the root-mean-square speed of the molecules be the highest at 200 C? A) HCl B) Cl2 C) SF6 D) H2O E) None. The molecules of all gases have the same root-mean-square speed at any given temperature. 28) Of the following, only is impossible for an ideal gas. A) V 1 V2 = T 1 T2 B) V 1 T1 = V 2 T2 C) V 1 V2 = T 1 T2 = 0 D) V2 = T 2 T1 V 1 E) V1T1 = V2T2 A-5
29) There are more types of unit cells than just cubic. The picture here shows an end-centered orthrhombic unit cell. How many atoms can be said to "belong" to a unit cell of this type? A) 1 B) 2 C) 6 D) 8 E) 10 30) Identify the place which has the lowest boiling point of water. A) Death Valley, 282 feet below sea level B) Denver, Colorado, 5280 feet C) Mt. Everest, 29,035 feet D) A pressurized passenger jet, 35,000 feet E) New Orleans, sea level A-6
Answer Key Testname: CHM2045 F13 E03 FINAL DRAFT 1) D 2) B 3) E 4) E 5) A 6) A 7) A 8) D 9) E 10) C 11) B 12) E 13) B 14) D 15) D 16) B 17) D 18) A 19) C 20) A 21) A 22) D 23) B 24) E 25) B 26) A 27) D 28) E 29) B 30) C A-7