Formulas/equations Molar volume at STP (0 ffi C= K, 1atm)=22.4L temperature conversions: T(F)=(9/5)T(C)+32, T(C)=(5/9)[T(F)-32] Ideal gas law: P

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1 Final Exam - Spring 2001 Chem. 1021, MWF 11:15-12:05 class (sec. 009) Prof. Darrin M. York NAME: EXAM ID #: THIS TEST IS VERSION A MARK THE VERSION ON THE BUBBLE SHEET NOW. INSTRUCTIONS: DON'T FORGET TO ENCODE YOUR NAME, STUDENT ID #, AND EXAM VERSION (A, B, OR C) ON THE BUBBLE SHEET PROVIDED. THE RANDOM EXAM ID # APPEARING ON YOUR BUBBLE SHEET WILL BE USED FOR THE PURPOSE OF POSTING YOUR SCORE. RECORD IT IN THE SPACE ABOVE NOW. YOU MAY NOT KEEP THE FINAL EXAM - FOR THE PURPOSES OF CHECKING YOUR FINAL GRADE, WRITE DOWN YOUR EXAM ID # AND SAVE IT. GRADES WILL BE POSTED ON THE WEB PAGE. GOOD LUCK! 1

2 Formulas/equations Molar volume at STP (0 ffi C= K, 1atm)=22.4L temperature conversions: T(F)=(9/5)T(C)+32, T(C)=(5/9)[T(F)-32] Ideal gas law: PV = nrt Dalton's law: P total = P 1 + P 2 + P 3 + Hydrogen energy levels: E n = J (Z 2 =n 2 ) E n1!n 2 = J Z 2 (1=n 2 2 1=n 2 1) photon energy: E photon = hν =hc/ kinetic theory (rms velocity): u rms =(3RT=M) 1=2 Enthalpy: H=E+PV; H= E+ (PV); E = q + w; for PV work: w=-p V H ffi rxn P P P = n p H ffi f (products) P n r H ffi f (reactants) P H = D(bonds broken) D(bonds formed) where is a sum of terms, and D is the bond energy per mole of bonds (always positive). specific heat capacity: E = s m T Graham's law: (Rate 1 /Rate 2 )=(M 2 =M 1 ) 1=2 Coulomb's law (in J): E= J nm Q 1 Q 2 r Constants Avogadro's number (N A )=6: mol 1 Ideal gas constant R= L atm/k mol=8.314 J/K mol Planck's constant: h= J s Speed of light: c= m s 1 1 cm 3 =1 ml= L 1 nm =10 9 m 1 atm = 760 torr Atomic mass unit (amu): 1 amu = kg = 1 g/mol electron mass: m e = kg Table 4.1 (Solubility Rules for Salts in Water) 1. Most nitrate (NO 3 ) salts are soluble. 2. Most salts containing the alkali metals ions (Li +,Na +,K +,Cs +,Rb + ) and the ammonium ion (NH + 4 ) are soluble. 3. Most chloride, bromide, and iodide salts are soluble. Notable exceptions are salts containing the ions Ag +,Pb 2+, and Hg Most sulfate salts are soluble. Notable exceptions are BaSO 4, PbSO 4, Hg 2 SO 4, and CaSO Most hydroxide salts are only slightly soluble. The important soluble hydroxides are NaOH and KOH. The compounds Ba(OH) 2, Sr(OH) 2, and Ca(OH) 2 are only marginally soluble. 6. Most sulfide (S 2 ), cabonate (CO 2 3 salts are only slightly soluble. ), chromate (CrO2 4 ), and phosphate (PO3 4 ) 2

3 MO diagrams for homonuclear diatomic molecules The unit cell for a nickel arsenide crystal 3

4 Part I: Material covered on midterm Exam I 1. Which one of the following statements about atomic structure is false? a) The electrons occupy a very large volume compared to the nucleus. b) Almost all of the mass of the atom is concentrated in the nucleus. c) The protons and neutrons in the nucleus are very tightly packed. d) The number of protons and neutrons is always the same in the neutral atom. e) The number of protons plus electrons is always the same in the neutral atom. 2. An isotope, X, of a particular element has an atomic numberof7andamass number of 15. Therefore, a) X is an isotope of nitrogen. b) X has 8 neutrons per atom. c) X has an atomic mass of d) a and b e) a, b and c 3. The reaction of 11.9 g of CHCl 3 with excess chlorine produced 12.6 g of CCl 4 (carbon tetrachloride) according to: What is the percent yield? a) 94.4 % b) 48.6 % c) 82.2 % d) 51.4 % e) 46.2 % CHCl 3 +Cl 2! CCl 4 +HCl 4

5 4. Give the correct coefficients (w, x, y, z) that balance the following reaction: a) w=1, x=2, y=1, z=6 b) w=1, x=2, y=2, z=2 c) w=1, x=1, y=1, z=6 d) w=6, x=2, y=1, z=1 e) w=2, x=4, y=2, z=6 wh 2 SnCl 6 + xh 2 S! ysns 2 + zhcl Λ 5. A mixture contained no fluorine compound except methyl fluoroacetate (FCH 2 COOCH 3, molar mass g/mol). When chemically treated, all the fluorine was converted to calcium fluoride (CaF 2, molar mass g/mol). The mass of CaF 2 obtained was 12.1 g. Find the mass of FCH 2 COOCH 3 in the original mixture. a) 92.0 g b) 28.5 g c) 24.2 g d) 14.3 g e) 12.1 g 6. In the reaction 2H 2 (g)+o 2 (g)! 2H 2 O(g), O 2 is a) oxidized. b) reduced. c) the electron donor. d) the reducing agent. e) aandd 5

6 7. What volume of 2.0 M NaOH is required to neutralize 100 ml of 5.0 M H 2 SO 4? a) 400 ml b) 500 ml c) 1L d) 2L e) none of these 8. Which gas has the highest density (at the same temperature and pressure)? a) Ne b) Cl 2 c) CH 4 d) NH 3 e) all the gases have the same density 9. A 4.37-g sample of a certain diatomic gas occupies a volume of 3.00 L at 45 ffi C and 1 atm. Identify the gas. a) F 2 b) N 2 c) H 2 d) O 2 e) Cl What volume of carbon dioxide gas measured at STP will be formed by the reaction of 1.30 mol of oxygen gas with mol of ethanol (CH 3 CH 2 OH) according to the reaction: a) 8.70 L b) 19.4 L c) 28.0 L d) 40.3 L e) 91.9 L CH 3 CH 2 OH(l)+3O 2 (g)! 2CO 2 (g)+3h 2 O(g) 6

7 Part II: Material covered on midterm Exam II 11. A gaseous mixture containing 1.5 mol Ar and 3.5 mol CO 2 has a total pressure of 7.0 atm. What is the partial pressure of CO 2? a) 5.8 atm b) 6.1 atm c) 3.0 atm d) 4.9 atm e) 2.1 atm 12. At 2400 K, the molecules of an unknown gas X have the same root-meansquare velocity as He gas at 300 K.What is the gas X? a) Ne b) Ar c) H 2 d) N 2 e) O 2 Λ 13. Using the information below, calculate the H f for PbO(s) PbO(s)+CO(g)! Pb(s)+CO 2 (g) H = kj H f for CO 2 (g) kj/mol H f for CO(g) kj/mol a) kj/mol b) kj/mol c) kj/mol d) kj/mol e) kj/mol 7

8 14. How much heat is required to raise the temperature of a 6.21-g sample of iron [specific heat = J/(g ffic)] from 25 ffi C to 79.8 ffi C? a) 70.0 J b) 101 J c) 386 J d) 756 J e) 153 J 15. How many of the following molecules have a permanent dipole moment? a) 0 b) 1 c) 2 d) 3 e) 4 SF 2, NH 3, CCl 4, PCl Which of the following exhibits the correct orders for both increasing atomic radius and increasing electronegativity, respectively? a) radius: S < O < F, and electronegativity: S < O < F b) radius: F < S < O, and electronegativity: O < S < F c) radius: S < F < O, and electronegativity: S < F < O d) radius: F < O < S, and electronegativity: S < O < F e) none of these 8

9 17. The electron configuration of Ti 2+ is: a) [Ar]4s 2 b) [Ar]4s 1 3d 1 c) [Ar]3d 2 d) [Ar]4s 2 3d 2 e) none of these 18. Which of the following statements about quantum theory is incorrect? a) There is a fundamental limitation as to to how precisely we can know both the position and momentum of an electron simultaneously. b) Lower energy orbitals are filled with electrons before higher energy orbitals. c) When filling orbitals of equal energy, two electrons will occupy the same orbital with paired spins before filling a new orbital. d) No two electrons in the same atom can have the same four quantum numbers. e) All of these are correct. 19. Which of the following combinations of quantum numbers (n, l, m and m s ) is not allowed? a) n=1, l=1, m=0, m s =1/2 b) n=3, l=0, m=0, m s =-1/2 c) n=2, l=1, m=-1, m s =1/2 d) n=4, l=3, m=-2, m s =-1/2 e) n=4, l=2, m=0, m s =1/2 20. In the hydrogen spectrum, what is the wavelength of light associated with the n =3! n = 2 electronic transition? a) nm b) nm c) nm d) nm e) nm 9

10 Part III: Material covered on midterm Exam III 21. Given the following bond energies: C C C =C C O C =O C H O H O O 347 kj/mol 614 kj/mol 358 kj/mol 799 kj/mol 413 kj/mol 467 kj/mol 146 kj/mol estimate the H for the reaction (Note: H 2 O 2 is H-O-O-H): a) -349 kj b) -585 kj c) -544 kj d) +585 kj e) +349 kj H 2 O 2 +CH 3 OH! H 2 CO + 2H 2 O 22. Select the correct molecular structure for ICl 4 a) square pyramidal b) tetrahedral c) square planar d) see-saw e) octahedral 23. Select the correct molecular structure for SO 2 3 a) trigonal pyramidal b) trigonal planar c) T-shaped d) trigonal bipyramidal e) octahedral 10

11 Λ 24. Calculate the lattice energy for NaF(s) given the following information: sublimation energy for Na(s) +109 kj/mol H f for F(g) +77 kj/mol first ionization energy of Na(g) +495 kj/mol electron affinity of F(g) -328 kj/mol H f for NaF(s) -570 kj/mol a) -217 kj/mol b) -923 kj/mol c) kj/mol d) kj/mol e) none of these 25. What is the formal charge on boron in the H 3 N-BF 3 molecule? a) -2 b) -1 c) 0 d) 1 e) For how many of the following does the bond order decrease if you take away one electron from the neutral molecule (refer to the MO diagram on inside page)? B 2,C 2, N 2,F 2 a) 0 b) 1 c) 2 d) 3 e) 4 11

12 27. The hybridization of xenon in XeF 4 is a) sp 2 b) sp 3 c) sp 4 d) dsp 3 e) d 2 sp The molecule CH 3 C CCH 2 CH 2 Cl is named: a) 1-chloro-3-pentyne b) 5-chloro-2-pentene c) 1-acetylenyl-3-chloropropane d) 5-chloro-2-pentyne e) 1-chloro-3-pentene 29. How many isomers of C 2 Cl 2 Br 2 are there? a) 1 b) 2 c) 3 d) 4 e) Of the series of diatomic molecules: O 2,O 2,O + 2, O 2+ 2 which paramagnetic molecule has the shortest O-O bond length (refer to the MO diagram on inside page)? a) O 2 b) O 2 c) O + 2 d) O 2+ 2 e) none are paramagnetic 12

13 Part IV: Material from the last part of the class (after Exam III) 31. The boiling point of methanol is much higher than that of ethane. This is primarily due to a) Strong London dispersion forces in methanol. b) Hydrogen bonding in methanol. c) Long-ranged ion-ion forces in methanol. d) The carbon-oxygen double bond in the methanol. e) none of these 32. Identify the type of organic compound shown: CH 3 CH CH 3 j NH 2 a) nitrocarbon b) primary amine c) secondary amine d) tertiary amine e) none of these 33. Identify all the functional groups present in the following organic compound: 1) ketone, 2) aldehyde, 3) carboxylic acid, 4) ether, 5) ester, 6) alcohol O O k k CH 3 C O CH 2 CH 2 COH a) 2,6 b) 1,4,6 c) 1,3,4 d) 3,5 e) 1,5,6 13

14 34. Small molecules such as water are formed with the extension of the polymer chain in which kind of polymerization reaction? a) crosslinking b) condensation c) addition d) substitution e) vulcanization 35. What monomer(s) is (are) needed to produce the below polymer? CH 3 CH 3 CH 3 j j j ( C CH 2 C CH 2 C CH 2 ) n j j j CH 3 CH 3 CH 3 a) CH 2 =CH 2 and CH 3 CH = CH 2 b) CH 2 = C(CH 3 ) 2 c) CH 3 CH = CHCH 3 d) CO and CH 2 =CH 2 e) none of the above 36. Name the following compound Cl j CH 3 CH CH C CH(CH 3 ) 2 j CH 2 j CH 3 O k a) 2-chloro-3-ethyl-1-isopropylbutanone b) 3-chloro-2-ethyl-5-methyl-4-hexanone c) 2-butyl,chloro,isobutyl methane d) 4-chloro-2,5-dimethyl-3-heptanone e) 3-methyl-4-chloro-1-isopropylpentanone 14

15 37. Which one of the following decreases as the strength of the attractive intermolecular forces increases? a) The heat of vaporization. b) The normal boiling temperature. c) The extent of deviations from the ideal gas law. d) The surface tension of a liquid. e) The vapor pressure of a liquid. 38. Which of the following statements is true about a p-type silicon semiconductor? a) It is produced by doping Si with P or As. b) Electrons are the mobile charge carriers. c) It does not conduct electricity as well as pure Si. d) All are true. e) None is true. 39. A metal is typically characterized by: I. Efficient conduction of heat and electric current. II. A large energy gap between the filled MOs of the metal and the empty MOs that form the conduction band. III. Nondirectional covalent bonding involving highly delocalized electrons. a) I b) II c) III d) I and III e) I, II and III Λ 40. The unit cell for a nickel arsenide crystal is shown on the inside page. What is the empirical formula for the compound? a) NiAs b) Ni 2 As c) Ni 3 As d) Ni 6 As 2 e) NiAs 2 15

Formulas/equations Molar volume at STP (0 ffi C= K, 1atm)=22.4L temperature conversions: T(F)=(9/5)T(C)+32, T(C)=(5/9)[T(F)-32] Ideal gas law: P

Formulas/equations Molar volume at STP (0 ffi C= K, 1atm)=22.4L temperature conversions: T(F)=(9/5)T(C)+32, T(C)=(5/9)[T(F)-32] Ideal gas law: P Final Exam - Spring 2001 Chem. 1021, MWF 8:00-8:50 class (sec. 001) Prof. Darrin M. York NAME: EXAM ID #: THIS TEST IS VERSION A MARK THE VERSION ON THE BUBBLE SHEET NOW. INSTRUCTIONS: DON'T FORGET TO