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PART A. (4 Pints each) Chem. 15 Exam # 01 Fall Day Test 1. What element(s) is/are underging xidatin in the fllwing reactin? a. Only C in methane b. Only C in carbn dixide CH4 g O( g) CO g HO g c. C in bth methane and carbn dixide 4 t 4 d. Bth C and H in methane e. Only O in xygen. 75 ml f 1.0 M KOH is diluted t 00. ml by adding abut 15 ml f water. What is the apprximate new cncentratin f KOH? a. 0.8 M c. 0. M e. 0. M 75mL 1.MKOHx 0.49MHCl b. 0.4 M d. 0.5 M 00mL. g aluminum brmide is disslved in enugh water t make 15 ml f slutin. What is the apprximate cncentratin f the brmide ins? a. 0.5 M b. 0.1 M c. 0. M d. 0. M e. 0.4 M MM AlBr 7.0 x79.9 67 g/ ml galbr 1mlAlBr x /0.15L0.090 ml/ L0.090M AlBr 1 67 g Cl 0.09 x 0.7M 0.M 1 sig. fig. 4. Excess zinc is added t 150 ml f 0.90 M HCl. The reactin is: Zn s HCl aq ZnCl aq H g. Apprximately what vlume f hydrgen gas is prduced at STP (0 ᵒC and 1 atm). a..0 L Zn s HCl aq ZnClaq Hg b..0 L Excess 150 ml?ml c. 0.5 L d. 0.8 L 0.90M e. 1.5 L 0.9 ml HCl 0.15L 1ml H x x 0.068 ml H L 1 ml HCl 5. 100 ml f hydrchlric acid is in a beaker. What is its apprximate cncentratin if 60.0 ml f it is HCl aq KOH aq H O l KCl aq neutralized by 5 ml f 0.80 M KOH? The reactin is: a. 0.4 M b. 0. M c. 0.7 M d. 0. M e. 0.5 M q HCl aq KOH aq H O l KCl a 60.0 ml 5 ml?m 0.80M 0.8 ml KOH 0.05L 1ml HCl x x L 1 1ml KOH Cnentratin HCl. 6. The density f an unknwn gas is 1.g/L at STP. What is the mlar mass f the gas? a. 54 g/ml L atm b. 18 g/ml 0.081 7K V RT K ml.4l c. 8 g/ml PV nrt; n P 1atm ml d. 0.05 g/ml 1.g.4L e. 0.04 g/ml MM x 7.6 g/ ml L ml 0.08 ml HNO 0.060L 0.08 ml HCl At STP, 1 ml =.4 L 0.068 ml H.4L 1 1ml nrt r use V P V x 1.5 ml 0.47 0.47M HCl L L
Chem. 15 Exam # 01 Fall Day Test 7. Which f the fllwing gases has the secnd highest average velcity at 00 K? a. Cl O RT vrms. S the smaller the mlar mass, the higher the average velcity b. SO M c. SOCl r they all have the same kinetic energy which equals 0. 5m v. d. Cl This gives the same cnclusin. e. All average velcities are the same. MM SOCl 1671119, ClO 87, SO 80, Cl 71 8. Helium at atm is in a 50 L cntainer. N at at atm is in a 0 L cntainer. Bth cntainers are cnnected t a balln whse riginally vlume is zer. The cnnecting valves are pened and the balln is filled. At equilibrium, the pressures in the cntainers and balln are abut 1 atm. What is the apprximate vlume f the balln? a. 110 L b. 10 L c. 150 L d. 170 L e. 190 L PV nrt cnstant; PV P V ; Initially ignre N and calculate fr He alne. He He P atm Vf V1 50L x 100L P 1atm He 1 He f N N N 1 f 1 N Pf 1 1 f f P atm Similarly, V V 0L x 90L 1atm V f V V 190 L; V V V V 190 500110L He N balln He N f f f 1 1 9. As a gas expands against an external pressure f 1.70 atm frm 1.0 L t 18.0 L, it lses 800 J f heat t the envirnment. what is its change in internal energy, ΔE? (Recall, 101. J = 1 L atm.) a. 1,800 J 101.J b. -00 J q800 J; wpextv 1.70atm6.0L x 100 c. 00 J L atm d. -1,800 J E qw1,80j 1,800J e. -800 J 10. An dd way t measure mass. An unknwn mass f water is in a Styrfam calrimeter f negligible heat capacity. The initial T f the water is 5.0 ᴼC. After 100. g f irn at 65.0 ᵒC is added, the equilibrium T is 15.0ᴼC. What is the apprximate mass f the water? The specific heat f irn and water are 0.45 J/( g ᵒC) and 4.184 J/( g ᵒC), respectively. a. 50 g b. 70 g c. 90 g d. 10 g e. 140 g q Fe q HO 0 m C T m C T 0 Fe HO Fe s Fe HO s HO 0.45J 4.184J 100 15.0 65.0 15.0 5.0 0 g C g C, 50 41.84 J/ g z 0 g C z C J z 54g
Chem. 15 Exam # 01 Fall Day Test 11. Using Hess s Law, calculate ΔH fr the fllwing reactin: CCl g 4HCl g CH g 4Cl g Use the fllwing reactins and ΔH : a. 11.4 kj b. 05.7 kj c. 54.9 kj d. 14. kj e. -16,5 kj 4 4 4 4 C s H g CH g H 74.6kJ C s Cl g CCl g H 95.7kJ H g Cl g HCl g H 9.kJ 4 74.6 4 95.7 C s H g CH g H kj CCl g C s Cl g H kj 4HCl g H g Cl g H 9.kJ 184.6kJ CCl g 4HCl g CH g 4Cl g H 05.7kJ 4 4 1. Hw many mles f phtns are cntained in a burst f yellw light (589 nm) frm a sdium lamp that cntains 609 kj f energy? a. 1 ml b. ml hc 6.6x10 4 J sx10 8 m/ s 19 19.8x10 J Eph 1phtn hf.8x10 J r E 9 ph c. ml 589x10 m 1phtn d. 4 ml 609, 000J 1phtn 1ml phtn e. 5 ml x x.00ml phtns 19 1.8x10 J 6.0x10 phtn 1. Which electrn rbital resembles a dumbbell r peanut? a. s c. f b. p d. d 14. Hw many unpaired electrns des a sulfur atm have and is it diamagnetic r paramagnetic? a. 4 and paramagnetic b. 4 and diamagnetic c. and paramagnetic d. and diamagnetic e. Nne f the abve 15. An electrn in which electrn rbital requires the greatest phtn energy fr it t be inized? a. 1s b. p c. p d. d e. 4s It is analgus t being in a well--the deeper the well, the greater the K.E. needed t 16. Which set f quantum mechanical numbers fr an electrn in an s, p, d, r f rbital is nt pssible? a. d rbital: n=4, l=, ml =, and ms = +1/ b. p rbital: n=, l=1, ml = 0, and ms = +1/ c. 5p rbital: n=5, l=1, ml = -1, and ms = +1/ d. s rbital: n=, l=0, ml = 0, and ms = -1/ e. 5f: n=5, l=, ml =-, and ms = +1/ e. g 4 4 1 1. Full rbitals have n unpaired electrns. S Ne s p p p p p thrugh the baseball ut. 1 s electrns are the deepest in the well. x y z
Chem. 15 Exam # 01 Fall Day Test 17. Arrange the fllwing atms and in frm smallest t largest in size--n, N -, O, Ne. a. Ne, O, N, N b. Ne, O, N, N c. ONeN,,, N d. ONeNN,,, e. N, Ne, O, N 18-19. The fllwing reactin shws the reductin f irn (III) xide t irn by carbn: Fe O s C s 4 Fe s CO g H 467.9 kj Initial cnditins 50.0 g 7.0 g T save time the mlar mass f irn III xide is x55.8+x16 = 160. g/ml 18. What is the apprximate standard enthalpy f reactin fr 4 g f carbn, that is, 4g C are used up? a. 10 kj b. 0 kj c. 50 kj d. 100 kj e. 150 kj 0 467.9 kj 4 1 ml C 4 gc H gc x x 5.0 50kJ ml C 1g 1 19. Apprximately hw many grams f irn (III) xide remain after 4 g f carbn have reacted? a. 5 g b. 5 g c. 0 g d. 10 g e. 15 g 4gC 1ml C ml Fe O 160g Fe O 1 1g mlc 1ml x x x gfeo remaining xide 50 5.6 14.4gFeO 5.6 used up
Chem. 15 Exam # 01 Fall PART B (Each prblem is 1 pts) Day Test I. 4.00 L f ammnia gas at rm temperature ( ᵒC) and 70. trr are bubbled thrugh 150. ml f 0.75 M sulfuric acid in a 500 ml glass beaker. The acid-base neutralizatin reactins is: (a 1 ) (5 pts) What is the maximum yield in mles fr the ammnium sulfate? JUSTIFY. 70trr 1atm P x 0.961atm 1 760trr 0.961atm4L PV PV nrt; n 0.159ml NH RT L atm 0.0806 95K ml K 0.159 1ml NH NH g H SO ( aq) NH SO aq. 4 4 4 SO ml NH x 4 4 ml NH 4 SO 4 1 ml NH 0.0794 Smaller is crrect answer 0.75ml H SO 0.15L L 1ml NH SO 4 4 4 x x 0.11ml NH4 SO4 1 1mlHSO4 (a ) ( pts) Suppse the actual cncentratin f ammnium sulfate is 0. M. What is the percent yield f ammnium sulfate? 0.ml 0.15L x 0.0495ml ammnium sulfate L 1 actual yield 0.0495trr % yield x100% 6% theretical yield 0.0794trr (b 1 ) (4 pts) Cmplete and balance the fllwing precipitatin reactin. Yu must include (s) and (aq) fr credit. Al CH COO aq NH S aq 4 Al CH COO aq NH S aq Al S s 6NH CH COO aq 4 4 (b ) (1 pt) What is (are) the spectatr in(s)? NH4, CHCOO
Chem. 15 Exam # 01 Fall Day Test II. In parts (a) and (b) yu will calculate hw much ethanl is needed t bring a cup f water t the biling pint at ne atmsphere. The specific heat f water is 4.184 J/g /C. The fllwing reactin will be useful fr sme f parts (a)-(c). CHOHl Og CO g HOg H 1,5 kj 5 (a) (4pts) Hw much heat in kj will be required t raise the temperature f 50 g f water frm 5 C t 100 C? 50g 4.184J 75 C 1kJ qmcst x x x 78.5kJ 1 g C 1 10 J (b) (4pts) Suppse an alchl lamp is used t heat the water. Suppse further that all the energy released by the burning ethanl flame is transferred t the water. Hw many grams f ethanl are required t heat the water? USE 100 kj AS THE ANSWER FOR PART (a). THIS WAY PART (a) CAN BE MISSED WITH NO LOSE IN CREDIT. q H 1, 5 kj / ml C H OH surr 5 100kJ 1ml CH5OH 46.0g x x 1 1, 5kJ 1ml C H OH 5.7g Aside, the actual amunt needed t heat the water is.9 g. 78.5kJ 1ml C H OH 46.0g 1 1,5kJ 1ml C H OH 5 x x.9g 5 (c) (4pts) What is the the right may be useful. H f f C H 5 OH? Sme f the infrmatin in the table t H H CO H H Og H C H OH H O f f f 7 f x 1, 5 94 4 0 x 1, 5 1,514 79 kj / ml ΔH f Mlecule (kj/ml) CO (g) -111 CO (g) -94 H O (g) -4 H O (l) -86 Nte, t grader. If answer is -77.6 kj/ml, mark it wrng and bring t my attentin.