Exam 1 Solutions - r< If y Chemistry 105 Exam 1 Sept 24 2015 BCH Form 2 Page 1 Name ID ’ TA Lab Sec 1 Which of these substances are compounds ‘'Ar

Exam 1 Solutions - r< If y Chemistry 105 Exam 1 Sept 24...

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Unformatted text preview: r&lt; If y . Chemistry 105 Exam 1' Sept. 24, 2015 BCH Form 2 Page 1 Name: ID# ’ TA Lab Sec 1. Which of these substances are compounds? , ‘ 'Ar C02 H2 NagCO3 A. H2002 and N32003 (MP Q B. H2 and coz ' °‘ “WWW”; ' C. C02 and H2 I “A and NaZCO3 @o and Na2C03 2. A liquid has a density of 0.827 g/cm3. What is the volume of 5.4 mg of this liquid? A. - 3 6.5 mL 5,4/ 5 / 0M ‘ _ '3 ($6.5m “’03 ~ ' K. ———-/&quot;“L ' 5‘3&quot;”) “L c.- 6.4fL 01‘th [m3 D. 6.5 pL _3 ' E. 6.5nL 65 no «ML , ’M‘ : 4 Dr L ...'5 ’ M . lo 74L 3. Consider the numbers 56.13 and 4.2,. The product of these numbers (multiplying) contains significant digits, while the difference of these two numbers (subtracting) contains significant digits. (Fill in the blanks from the choices below, in order): '67.. I? . 2’ 4 _ a 2 y p 51-13 B 2,3 “(7— 4 i if —-‘/.z ',_____._. .C' 3'2 255',“ ) 0'1‘93 . D. 3, 3 . k ( E. 3, 4 SW &quot;k 3 379 (1‘5: 4. Convert 0.24 g/cm2 to pounds/m2. (1 pound = 1 lb = 454 g) A. 5.3x10-2lb/m2 2 ‘ . g _ a L ‘4 . 1.9 105 / 2 0~ oo 0m _ ’ B x 2Ibm ‘lix Had/z ' 6,3/ C .3 lb/m —'; 757 '2 _ ’—‘2&quot; D. 5.3x10-8Ib/m2 6'“ \9 7” ’h ‘ E. 1.9 x107lb/m2 Form 2 Page 2 Chemistry 105 Exam 1 Sept. 24, 2015 BCH 5. Consider the following chemical species: 883r2+ ' ‘ Zv $8 The number of protons, neutrons, and electrons in this species is: A. 50 protons, 38 neutrons, and 50 electrons. B. 38 protons, 38 neutrons, and 50 electrons. C. 88 protons, 50 neutrons, and 88 electrons. D. 38 protons, 50 neutrons, and 50 electrons. @ 38 protons, 50 neutrons, and 36 electrons. 6. Which choice below shows examples of the following groups of elements, in order? @ Si, F, Ne B. Ne, Fe, Na C. U, Br, Kr D. Mg, Kr, Fe E. K, CI, Xe Metalloid, Halogen, Noble Gas 7. Calculate the average atomic mass for imaginary element Z, if it has three isotopes with- the following masses and abundances: ' Z— 67 = 66.36 amu, 48.28 % Z— 69 = 68.29 amu, 21.34 % Z — 70 = 69.68 amu, 30.38 % A 65283mu MASS? awu n 0-7928)&quot; (68.2904‘01 x 0, {- . 69.55 (B; 66.11 L509. 08 W &quot; 0'30”) . 67.78 amu ‘ (E6838 amu 7 (3,778 am 8. What is the mass of 1.09 x 1021 Al atoms? ' t 4 ’ ' V - jg :- ;-:i::3-:. new A/ m. WW .. @4.88x1-o-29 ‘ 6-022x/094m Mao! A/ D. 1.81X10'3g . r E.2.05x101g ‘ r ’ D'ngeegn. Chemistry 105 Exam 1‘ Sept 24, 2015 BCH Form 2 Page 3 9. You are an eggfarmer, with 100 hens that produce 2 eggs per day. You collect 73,000 _ eggs per year. How 'many years would it take for you to collect 1 mol of eggs? ‘ A. 73,000 years /00 new x 2m ; 7’3” fig eyjf/yr @(101 8) years A“! C. 6(1023) years ‘ , u / ‘ ,— ‘ /c9 D. 4(1028) years E 6,027 7‘ ’0 e S ——L- z 8 &quot; 0 PS &quot;E. 1(10'19) Years 06 &quot;Lg 00° 9735 / 7 r 10. What is the molar mass of magnesium perchlorate, Mg(CIO4)2? . M3 : gm, st jlwl @2232 g/mol ‘ _ To , . B. 247.59/mol Cl *2 - ~qo C.151.59/mol o “3 ': 128.c90 D. 123.8 g/mol ________// E.- 75.8 g/mol 2,2 ,Z 11. You have asthma and are given a dose of the steroid called Prednisone, C21H2505, which has a molar mass of 358.4 g/mol. If you ingeSt 1.5(10'3) mol of C21H2505, how many molecules of Prednisone are now in your body? ' ' 7.3 '- xg-g-gggggi Lon/0‘34”! X com/a WM. F 910%” Cc?9.0(1020) /’mo/ « &gt; 7110(8’IQ/fis‘ D. 6.0(10'3) E. 1.5(10-3) 12. There are many hormones in plants that regulate growth. You decide to study plant hormones by examining the gases that are released by plants. A laboratory analysis of one hormone sample contained only 24.5 g nitrogen (N—atoms) and 70.0 g of oxygen (O-atoms). Calculate the empirical'formula of this compound. A. 'N03 .2153 IO n “d ‘- Z'Jf 1M N- NO IL/-0/v2 _ N205 D. N025 ' E. N204 7,003] O /‘ (“£2159 : 4/,37) m7 0 2.; N a Mr Form 2 Page 4 Chemistry 105 Exam 1 Sept.‘24, 2015 BCH 13. Give the formulas corresponding to the following names Vanadiumlllllnitrate ' beryllium chloride A. V(NO3) BeClg . ___. B. V(N02)3 BeCl2 Nos C. ‘ V3(N03) BeCl2 ' D. V(N03) BeCl @ V(N03)3 A BeCl2 14. What is the correct formula for nickel(lll) sulfate? A VN'(SO ) :3? 6642— . l 3 . B. Ni38 ——&gt; NI 1 @005 c. Ni83 ' ' ‘ ' @Ni2&lt;804&gt;3 E.‘ Ni3(SO4) 15. The US Food and Drug Administration recommends that a person consume less than 2.4 g of sodium per day. What mass of NaCl (in'grams) can you consume and still be within the FDA guidelines? Wis... : 5/ :2 W/ B. 0.19 3194 j IUQ _ C. 22.99 D. 2.49 E. 58.49 16. Hydrofluoric acid, HF, is an incredibly poisonous acid that is often used in etching glass (SiOg) via the following reaction: a so; + b HF e c HZSiFe + d H20. The coefficients for the balanced equation are A. a=1,b=2,c=1,d=1 B. a=1,b=6,c=r ,d=2 c. a=2,b=2,c=1,d=2 a=1,b=1,c=1,d=‘l f @a=1,b=6,c=1,d=2 Chemistry 105 Exam 1' Sept 24, 2015 BCH Form 2 Page 5 17. Copper reacts with nitric acid to produce copper(ll) nitrate, nitrogen dioxide gas, and water: - ' Cu(s) + 4 HN03 (aq) a Cu(N03)2 (aq) + 2 N02 (9) + 2 H20 (I) 0.500 9 2.00 9.500 ‘ If you have 0.500 moles of Cu, then: ' ‘ A. you need at least 2.00 moles of HNO3 to produce 1.00 moles of Cu(N03)2. B. you need at least 2.00 moles of HNO3 to produce 2.00 moles of Cu(NO3)2. C. you need at least 0.125 moles of HN03 to produce 0.500 moles of Cu(NO3)2. you need at least 2.00 moles of HN03 to produce 0.500 moles of Cu(NO3)2. E. you need at least 0.250 moles of HNO3 to produce 0.500 moles of Cu(N03)2. 18. Aspirin is produced by the reaction of salicylic acid (C7H503, 138.1 g/mol) and acetic anhydride (C4H503, 102.1 g/mol) C7H603(S) + C4H6030) 9 C9H804(S) + C2H402(|) If you mix 5.00 grams cf each reactant, how many grams of aspirin (180.2 g/mol) can be theoretically obtained? em . 96' 6'00 SGIIC¥,{1w—/__ 2‘th :- 8.82 g 5 Sang esp L . 72. 6.52 g _ D. g 5 0 F&quot; / f / l 0 2 0 E. 3.839 ’ °j 0” C 6,31. ,3 w x 4L2 7 802-3 /02-/9 ' / Mr 4‘Ct’7‘c {M/ “7 I 19. If the reaction of ammonia with excess oxygen produces a 38.2 % yield of NO, how many grams of NH3 must be reacted with excess oxygen to yield 17.5 g of NO? 4NH3(9) + 502(9) 9 4N0(9) + 6 H20 (9) A. 32.2 B. 45.83 / H00 Qwo/IW/z x [7’05 7 M73 c. 3.799 172?? Mo K 4‘” “ &quot; 30.015 A90 7%! No many}, 3 M S 3 mg @1032, x/fe((9 Form 2 Page 6 Chemistry 105 Exam 1 Sept. 24, 2015 BCH 20. Which of the following will be soluble in water: LiOH, Mg(OH)2, Cu(OH)2, and Fe(OH)3? ' l ' ' soak (in P“ 95 A. 'Cu(QH)2 and Fe(OH)3 ‘ B. Mg(OH)2 and Cu(OH)2 C. LiOH, Mg(QH)2. and Fe(OH)3 'LiOH and Mg(OH)2 @ LiOH only 21. Write the net ionic equationtgr the reaction of limestone (CaCOg) with a strong acid. .k‘ “A. @Caco3(s) + 2H+(aq)' a ’Ca2+(aq) + 002(9) + H20(l) B. CaO(s) + 2H+(aq) a Ca2+ (aq) + H200) c. .Ca(s) + 2H+(aq) a Ca2+ (aq) + H2 (9) - D. CaC03(s) + 2H+(aq) a oa2+(aq) + HzCO3(s) E. Ca\003(s) + 2HC|(aq) 9 K+(aq) +_ CaCI2(aq) + H2003(aq) 22. Which of the following are oxidation-reduction reactions? 1. Zn (3) + CuSO4(aq) a ZnSO4‘(aq) .+ Cu (5) 72960074 2- PblC|O4)2(aq) + 2K|(aq) 9 Pb|2(s) + 2NaClO4(aq) I pea/0 3. CaCOg(aq) a C02 (9) + CaO(s) 305 8mm; A. Reactions 1 &amp; 2 . Reactions 1 &amp; 3 . Reactions 2 &amp; 3 B C Reaction 2 only Reaction 1 only 23. If 5.15 g FeCl3 is dissolved in enough water to make exactly 150.0 mL of solution, what is the molar concentration of chloride ion? @635M , .. . 16.7M /JWK C. 0.103M [W D. 0.212M E. 0.578M ‘ F. - - 310:7 Feasx hwU‘ECG X3m(C/ “’21 2 3 Fe“? /%o/. 55:? ' 079,0 7“ x (000 cut ; aim/l Page 7 Chemistry 105 Exam 1 Form 2 Sept. 24, 2015 ’ BCH 24. If 5.00 mL of 0.314 M KOH is diluted to exactly 125 mL with water, what is the concentration of the resulting solution? A. 0.127M PM \)\ ”’ MLQL 3 3:211” (o-3va&gt;=°°&gt;= Mam) D. 5.02 x 10:4 M ' . L [email protected]&gt;&lt;10'2M M7— : 0—o(2é ‘25. A 0.3000 9 mixture contains soda ash (Na2C03, 105.99 g/mol) and several unreactive compounds. If it is titrated with 17.66 mL of 0.1187 M HCI, what is the percent , composition (mass percent) of the soda ash in the mixture? Na2CO3(aq) + 2HC|(aq) 9 2NaC|(aq) + H20(l) ‘+ C02 (9) @3703 % B. 74.06% C. 11.11% D. 22.22% E. 57.91% ‘ 3/114 ( I - V . 010/766 A x Q/’8?W°’ “(C/K a “6&amp;3 X /o§“.?? ,7 Aid, 65 CHEM 105 Fall 2015 Data Page for Exam 1 &quot;Constants and Equations ' Avogadro’s number: NA = 6.022 X 1023 a K =. °C + 273.25 °c=t°F—32)/1.8‘ Table 4.1 Solubility'Rules for Ionic Compounds in Water Compounds Containing the Following Ions ' E , . - ' . ' ‘ are Generally Soluble xcePUOHS . When these ions pair with Ag+, Hg22+, or Pb” ' the resulting compounds are insoluble ‘ When these pair with 11+, Na: K+, or NH], the resulting compounds are soluble. When Sz‘pairs with Ca2+, Si”, or Bay“, the resulting compound is soluble. When OH~ pairs with Ca2+, 819+, or 3212+ the resulting compound is slightly soluble When these pair With Li+, Na”: IC, or NH4+, ‘ the resulting compounds are soluble. A ‘ ...
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