MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Transcription

1 Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A gas at a pressure of 10.0 Pa exerts a force of N on an area of 5.5 m2. A) 18 B) 0.55 C) 1.8 D) 5.5 E) 55 1) 2) A gas at a pressure of 325 torr exerts a force of N on an area of 5.5 m2. A) 59 B) C) D) E) 2.4 2) 3) A pressure of 1.00 atm is the same as a pressure of of mmhg. A) B) 193 C) 101 D) E) ) 4) A closed-end manometer was attached to a vessel containing argon. The difference in the mercury levels in the two arms of the manometer was 12.2 cm. Atmospheric pressure was 783 mmhg. The pressure of the argon in the container was mmhg. 4) A) 882 B) 661 C) 771 D) 795 E) 122 5) A gas vessel is attached to an open-end manometer containing a nonvolatile liquid of density g/ml as shown below. 5) The difference in heights of the liquid in the two sides of the manometer is 43.4 cm when the atmospheric pressure is 755 mmhg. Given that the density of mercury is 13.6 g/ml, the pressure of the enclosed gas is atm. A) B) C) D) E) ) A sample of gas (24.2 g) initially at 4.00 atm was compressed from 8.00 L to 2.00 L at constant temperature. After the compression, the gas pressure was atm. 6) A) 8.00 B) 16.0 C) 4.00 D) 2.00 E) ) A balloon originally had a volume of 4.39 L at 44 C and a pressure of 729 torr. The balloon must be cooled to C to reduce its volume to 3.78 L (at constant pressure). 7) A) 38 B) 273 C) 72.9 D) 546 E) 0 8) If g of a gas occupies 10.0 L at STP, g of the gas will occupy L at STP. A) 50.8 B) 12.9 C) 5.08 D) 25.5 E) ) 1

2 9) A gas vessel is attached to an open-end manometer filled with a nonvolatile liquid of density g/ml as shown below. 9) The difference in heights of the liquid in the two sides of the manometer is 32.3 cm when the atmospheric pressure is 765 mmhg. Given that the density of mercury is 13.6 g/ml, the pressure of the enclosed gas is atm. A) B) 1.08 C) 1.01 D) 1.04 E) ) A sample of an ideal gas (3.00 L) in a closed container at 25.0 C and 76.0 torr is heated to 300 C. The pressure of the gas at this temperature is torr. 10) A) 76.5 B) 39.5 C) 146 D) 912 E) ) The molecular weight of a gas that has a density of 5.75 g/l at STP is g/mol. A) 3.90 B) 141 C) D) 129 E) ) 12) The reaction of 50 ml of N2 gas with 150 ml of H2 gas to form ammonia via the equation: N2 (g) + 3H2 (g) 2NH3 (g) will produce ml of ammonia if pressure and temperature are kept constant. 12) A) 50 B) 100 C) 250 D) 200 E) ) The density of chlorine (Cl2) gas at 25 C and 60. kpa is g/l. 13) A) 4.9 B) 0.58 C) 0.86 D) 1.7 E) 20 14) CO (5.00 g) and CO2 (5.00 g) were placed in a ml container at 50.0 C. The partial pressure of CO in the container was atm. 14) A) 4.02 B) 10.3 C) 1.60 D) E)

3 15) Automobile air bags use the decomposition of sodium azide as their source of gas for rapid inflation: 15) 2NaN3 (s) 2Na (s) + 3N2 (g). What mass (g) of NaN3 is required to provide 40.0 L of N2 at 25.0 C and 763 torr? A) 1.64 B) 71.1 C) 160 D) 1.09 E) ) The mass of nitrogen dioxide contained in a 4.32 L vessel at 48 C and Pa is g. A) 70.5 B) C) D) 53.5 E) ) 17) A tank containing both HF and HBr gases developed a leak. The ratio of the rate of effusion of HF to the rate of effusion of HBr is. 17) A) B) C) 4.04 D) 16.3 E) ) The molar volume of a gas at STP is L. A) 22.4 B) C) 14.7 D) E) ) 19) Of the following, is a correct statement of Boyle's law. A) V T = constant 19) B) n P = constant C) P V = constant D) PV = constant E) V P = constant 20) Of the following gases, will have the greatest rate of effusion at a given temperature. 20) A) NH3 B) HCl C) Ar D) HBr E) CH4 3

4 21) Which one of the following is a valid statement of Avogadro's law? A) V T = constant 21) B) V = constant P C) V = constant n D) PV = constant E) P T = constant 22) Of the following, is a valid statement of Charles' law. A) P T = constant 22) B) V = constant P C) V = constant n D) V T = constant E) PV = constant 23) For a molecule with the formula AB2 the molecular shape is. 23) A) linear or T-shaped B) linear or bent C) T-shaped D) trigonal planar E) linear or trigonal planar 24) According to VSEPR theory, if there are five electron domains in the valence shell of an atom, they will be arranged in a(n) geometry. 24) A) trigonal bipyramidal B) trigonal planar C) linear D) tetrahedral E) octahedral 25) The molecular geometry of is square planar. 25) A) XeF2 B) CCl4 C) XeF4 D) PH3 E) ICl3 4

5 26) The molecular geometry of the CHCl3 molecule is. 26) A) T-shaped B) trigonal planar C) bent D) tetrahedral E) trigonal pyramidal 27) The Cl-Si-Cl bond angle in the SiCl2F2 molecule is approximately. 27) A) B) 60 C) 120 D) 180 E) 90 28) The O-S-O bond angle in SO2 is slightly less than. 28) A) 90 B) C) 60 D) 120 E) ) The electron-domain geometry of a sulfur-centered compound is trigonal bipyramidal. The hybridization of the central nitrogen atom is. A) sp3 B) sp C) sp3d2 D) sp3d E) sp2 29) 30) The hybridization of orbitals on the central atom in a molecule is sp. The electron-domain geometry around this central atom is. 30) A) octahedral B) tetrahedral C) trigonal planar D) trigonal bipyramidal E) linear 31) The electron-domain geometry of the AsF6 - ion is octahedral. The hybrid orbitals used by the As atom for bonding are orbitals. A) sp2d2 B) sp2 C) sp3 D) sp3d E) sp3d2 31) 32) There are and bonds in the H2C C CH2 molecule. 32) A) 2, 2 B) 6, 2 C) 2, 6 D) 6, 4 E) 4, 2 5

6 33) There is/are bond(s) in the molecule below. 33) A) 0 B) 1 C) 2 D) 4 E) 16 34) The molecular geometry of the BrO3 - ion is. 34) A) tetrahedral B) trigonal planar C) trigonal pyramidal D) T-shaped E) bent 35) How many equivalent resonance structures can be drawn for the molecule of SO3 without having to violate the octet rule on the sulfur atom? 35) A) 2 B) 3 C) 1 D) 5 E) 4 36) Using the table of average bond energies below, the H for the reaction is kj. 36) H-C C-H (g) + H-I (g) H2C CHI (g) Bond: C C C=C H-I C-I C-H D (kj/mol): A) -506 B) -129 C) -931 D) +129 E)

7 The diagram below is the Born-huber cycle for the formation of crystalline potassium fluoride. 37) Which energy change corresponds to the electron affinity of fluorine? A) 5 B) 2 C) 4 D) 6 E) 1 37) 38) Which energy change corresponds to the first ionization energy of potassium? A) 5 B) 2 C) 4 D) 6 E) 3 38) 39) Using the Born-Haber cycle, the Hf of KBr is equal to. 39) A) Hf [K (g)] - Hf [Br (g)] + I1(K) - E(Br) + Hlattice B) Hf [K (g)] + Hf [Br (g)] + I1(K) + E(Br) + Hlattice C) Hf [K (g)] + Hf [Br (g)] + I1(K) + E(Br) - Hlattice D) Hf [K (g)] - Hf [Br (g)] - I1(K) - E(Br) - Hlattice E) Hf [K (g)] + Hf [Br (g)] - I1 - E(Br) + Hlattice 40) Using the table of average bond energies below, the H for the reaction is kj. 40) C O (g) + 2H2 (g) H3C-O-H (g) Bond: C-O C=O C O C-H H-H O-H D (kj/mol): A) -116 B) -276 C) +276 D) +735 E) ) How many equivalent resonance forms can be drawn for CO (carbon is the central atom)? 41) A) 2 B) 3 C) 1 D) 0 E) 4 42) Of the molecules below, the bond in is the most polar. 42) A) HI B) HCl C) HF D) HBr E) H2 7

8 43) Of the bonds C-N, C N, and C N, the C-N bond is. A) weakest/shortest B) intermediate in both strength and length C) weakest/longest D) strongest/longest E) strongest/shortest 43) 44) The formal charge on sulfur in SO4 2- is, where the Lewis structure of the ion is: 44) A) 0 B) -4 C) +2 D) +4 E) -2 45) The formal charge on carbon in the molecule below is. 45) A) +3 B) +1 C) -1 D) 0 E) +2 46) Given the electronegativities below, which covalent single bond is most polar? 46) Element: H C N O Electronegativity: A) O-N B) C-H C) N-H D) O-C E) O-H 47) A double bond consists of pairs of electrons shared between two atoms. A) 1 B) 2 C) 3 D) 4 E) 6 47) 48) A covalent bond between the same two atoms is the longest. A) double B) single C) triple D) They are all the same length. E) strong 48) 49) Which one of the following species has the electron configuration [Ar]3d4? A) Fe3+ B) V3+ C) Cr2+ D) Mn2+ E) K+ 49) 8

9 50) For a given arrangement of ions, the lattice energy increases as ionic radius and as ionic charge. 50) A) decreases, decreases B) decreases, increases C) increases, increases D) increases, decreases E) This cannot be predicted. 51) How many unpaired electrons are there in an O2- ion? A) 0 B) 1 C) 2 D) 3 E) This cannot be predicted. 51) 52) There are paired and unpaired electrons in the Lewis symbol for a phosphorus atom. 52) A) 2, 3 B) 4, 3 C) 2, 4 D) 0, 3 E) 4, 2 53) The bond angle marked a in the following molecule is about. 53) A) B) 180 C) 120 D) 90 E) 60 SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 54) Draw a Lewis Structure of actelyne (C2H2). Now draw the sigma & pi bonds based on the hybridization of the orbitals. (Balloon diagrams) 54) 9