CHAPTER 13 REVIEW PROBLEMS

Transcription

1 NAME:~ ~ PERIOD: CHAPTER 13 REVIEW PROBLEMS 1. Write the equilibrium expression for each of the following reactions and state whether the reaction is homogeneous or heterogeneous. a. 3 NO (g) <-7 N 2 0 (g) + N0 2 (g) [t-h..oj (N.OI.. ] b. [tjoj" Ni(CO)4 (g) <-4 Ni (s) + 4 CO (g) itoj"i C. CH 4 (g) + 2 H2S (g) <-7 CS2 (g) + 4 H2 (g) I< = [WaJ4[C~,J [CI..h,) [~2. SJ 2. d. 2 Ag (s) + Zn2+ (aq) <-42 Ag+ (aq) + Zn (s) L'-\5-tJ2 t 1"", ~-IJ 2. When the following reactions come to equilibrium, does the equilibrium mixture contain mostly reactants or ~--..., mostly products? a. N2 (g) + O2 (g) <-4 2 NO (g) K = 1.5 X Re\c.:rY-\ ~ T..5 b. 2 S02 (g) + O 2 (g) <-4 2 S03 (g) K = 2.5 x 10 9 ftwl)ij("t's 3. At loook, K, = 1.85 for the reaction a. Calculate the value of'k, for the reaction: S03 (g) <-4 S02 (g) + Yz O2 (g) lfr ~ ;<r = 1.'~.5 ~ \ o. SY I J b. Calculate the value of K, for the reaction: 2 S02 (g) + O 2 (g) <-7 2 S03 (g) c. Calculate the value ofk for the reaction in part (b) ,;) ~ I< L (.o3ji) (IOOO)J- 3,Yd.:; I( (,O/;J/80.21t;2) 1-< ~ as». 8~ s: ~ OVER --_.. _-- -~

2 4. Mercury (1) oxide decomposes into elemental mercury and elemental oxygen: 2 Hg-O (s) <-> 4 Hg (I) + Oz(g) a. Write the equilibrium constant expression for this reaction in terms of partial pressures. j{,a z: POd, b. Explain why we normally exclude pure solids and liquids from the equilibrium constant expression. ~ JJ\L tmk ~(:f)1r~ OAuJ ~ ~.l. 0Jl~J Gaseous hydrogen iodide is placed in a closed container at 425 C, where it partially decomposes to hydrogen and iodide: 2 HI (g) ~ H2 (g) + 12 (g) At equilibrium it is found that [HI] = 3.53 x 10-3 M, [H 2 ] = 4.79 X 10-4 M and [1 2 ] = 4.79 X 10-4 M. value of K at that temperature. K;: [r 01) [I..b ] [HIJ~ ( II.,q 'I.I ()- tf ) (!1.lq '" ft(') (3.53--,./O-5)1. Calculate the 6. The equilibrium for 2 NO (g) + CI 2 <-> 2 NOCI (g).is established at SOO.OK. An equilibrium mixture of the gases has partial pressures of atm for NO, atm for Cl,, and atm for NOCI. Calculate the K, for this reaction. (8oCt ') ~ - ( ~O)~(PoLY = (.d6-0)z- (.oqsoy( IlI) 7. a. How d~es the rea~tion :uotient differ from the e~uilibrium constant?.' /..M~J",.-f ~. J\J. ~ 1l-l,cn=fAL:l'"to ~ ~~ ~ d~j t:d-i; ~/Iv~' A Jh.~~.k~~jfu~~ b. If Q < K, in which direction will a reaction proceed in order to reach equilibrium? '---"u~~ ww ~ 16:Jk 1fl) ~~~~ ~~ ~~# c. What condition must be satisfied so Q = K?. ~~»vau1.~~~~ ~1kr~\'~ _._-_.._ _

3 8. At 100 C the equilibrium constant for the reaction COCh (g) <--> CO (g) + CI 2 (g) has a value ofk = 2.19 x Indicate whether each of the following mixtures ofcoch, Co, and Cl, are at equilibrium. If not, which direction must the reaction shift in order to achieve equilibrium? a. [COCI 2 ] = 2.00 x 10-3 M, [CO] = 3.30 X 10-6M, [Clj] = 6.62 x 10-1 M tv :. [COJ eel t ) :: (3. JO~ I 0-10 ) (~., ;l '1-1(J -, ) [COdt.) (Q.OO '( ) s: O.oOloq~3.: q ).l< SHI i='t LEl=, b. [COCh] = 4.50 x 10-2 M, [CO] = 1.10 X 10-7 M, [Clz] = 2.25 x 10-6 M [to J [ell.).=. 'lc.oul.] (1./. So 1-IO-J-) (I. /0 '1(0-1 )(.J. ss '1-10-") :. q - Q «\( S~IFT KlbHT c. [COCh] = M, [CO] = [Cl.] = 1.48 x 10-(;M -I;:' S. so ",,0 C! [eo J[c.Ql.J ~ (l.tf8'tlo-"')(i.4b'kfo-').: cj,icix/o-'o "y';: Leoc.h QX10-3 ~ =)<. AT EQUILI 'gtlljfr\ 9. At 100 C, K = for the reaction In an equilibrium mixture of the three gases, the concentrations of S02Ch == M and S02 = 0.052M. Calculate the equilibrium concentration of Cl-, I{.: [c t- J [soj. J -\.so~cl2-).: [t..hj(.os.;l).018' (.108') r, n) (.018') (.106) LCA~ : (.os~) 10. At 1200 K, K = 3.92 for the reaction CO (g) + 3 Hz (g)... CH 4 (g) + H20 (g) In an equilibrium equilibrium concentration of CH 4 K: [HaD) [thy J [eo J [H6l~ mixture of the gases, [CO] = 0.30 M, [H 2 ] = 0.10 M and [H 2 0] = 0.02 M. Calculate the 3. q ~ -= [C~ J (.03-) (. 30) ( I 0 ).1 LCI~1iJ.: (3,q~)(,.ao)(./0) (.001) 3 ~ fvl \ OVER

4 11. At 900 K the following reaction has a K, = (g) + O 2 (g) ~ 2 S03 (g) In an equilibrium mixture, the partial pressures of80 2 and O 2 are atm and atrn, respectively. Calculate the partial pressure of the S03.. K f :: (PsO!l);1 PS03 ;::..J(.3tJS)(.I".s).;}(7.sS~ ( Psoj ) 7- ( Poz- ) = C?so~)to 3 L\ S - (. I~S )Z (.1 S 5 ) = 12. The reaction is used to increase the ratio of hydrogen in synthesis gas (mixtures of CO and H 2 ). Suppose you start with 1.00 mole each of carbon monoxide and water vapor in a 50.0 L container. Calculate the equilibrium concentration of each substance. The equilibrium constant, K, is to - Cj) -t- -7 Hz-O ~) CO a Lj) +- fi:lcji I. () ~ 0 ~ 0 0 C -"I- -X +)( +'1 E,Qd-.-y o oa-}{ X X [(O~ 1[I-b J {Si [coj[hz-oj ::: o O)'-"/- (')() ("X.) 7~1 S 773/0b ; O~- X 701 s 77310h 'X - 'I[ Lto J :: O. 0/1 t( M [I-Id J :: & S fyl [I~l--O ] ;: O. 0 If l/ fvl [ to~j z: O M

5 r c E Y~,l: 13. Hydrogen and iodine react according to the followirig equation: Hz (g) + 12 (g) <-+ 2 HI (g) Suppose 1.00 mole Hz and 2.00 moles lz are placed in a 1.00 L container. Calculate the concentrations ofthe substances when the mixture comes to equilibrium at 458 C. K = 49.7.; /1.) CJlt Ia.~) ;:::2 d fir 9) 144.(.tJ (-/lici,')~ - (1.f)(tJS.7}(C{./.O) I. 00 d x = a (4 s. 7) -j( -x f;jy. 1_,)<: cj-x- d"f = 14Q.lt {p3.7!j-{t;7 V J.3 J.-3"1t~l qq,4 _, Llq, I~ + tjq, 1~1-; c{x. z, 2- d (l./~. 7 ). Cd-x) :: 1./q. 7:: (1- -x- ) (J -"I) «s <{ t./5. 7 ~ z: _ Il./q.1 Y- + qq, t( :::0 [Hi/. J.: 0, Oll& M [I<1]:: I.07M [H-1J ~ l.t71'1 14_ Lexan is a plastic used to make compact discs, eyeglass lenses, and bullet-proof glass. One of the compounds used to make Lexan is phosgene, COCI 2, an extremely poisonous gas. Phosgene decomposes by the reaction: COCh (g) <-> CO (g) + Ch (g) I C E For which K, = 6.8 X 10-9 at 100 D C. If pure phosgene at an initial pressure of 1.00 atrn decomposes, calculate the equilibrium pressures of all species. COcJ.~(jJ e-?' Co Cj) of ell. ~) x 1- X +x x +ll ( pco ) ( PtJ.l. ) ( Pcoc.1.~) ~ 'X-~~ _qx ~,t-x'o :: z. -s ~.i)...'iio ) ---(IuO.::, P: - S J t:co = 6. a 'f.. I 0 ~ I POl.. = s. a 'f. (0-5~ Pcoc.J.2..;,. 0 ~ OVER

6 15. Iodine dissociates to form iodine atoms according to the following reaction: h (g) (g) K = 5.6 X 10"12 If the initial concentration of iodine molecules is 0.45 M, determine the equilibrium concentrations of all species. -'7 S' -lil. LlxZ (rt) ~..:{ J... lg),\p'i-(o s: - /.q'l.io).j <.1.l{.5 -- (100 LIS 0 (.~s) (S,~ )(IO'~) :; L{)(2. ~4S -'-I~..., +...., -13 z. z:,47fo '!.IO 10 -,..."...,. ~. ~ ~ 10.=- X. <is -'Y- ;) '"'I 'X :: 7,c1 X 10-7 [I)~ _,~ (;J.y')l.- [IJ =. /.(e'l-io-t.. M I [r~j :; S.~ 110 s: ~ [r:~j: a,lis M ~"I-M~ 16. Consider the following equilibrium, for which 6.l-I < 0: 2 S02 (g) + O 2 (g)... 2 S03 (g) How will each of the following changes affect an equilibrium mixture of the three gases? a. O 2 (g) is added to the system. SHIFT \<\(,\4,. b. the reaction mixture is heated. S\-I1FT I.6'F"'T c. the volume of the reaction vessel is doubled. SHIFT Lf:FT d. a catalyst is added to the mixture. e. the total pressure of the system is increased by adding a noble gas. rjo CH4"'}0~ f. S03 (g) is removed from the system. SH I!=T 1<\ G I-h 17. Dinitrogen trioxide decomposes to NO and N0 2 in an endothermic process (6.H= 40.5 kl/mol). Predict the effect of the following changes on the position of the equilibrium; that is, state which way the equilibrium will shift (left, right, or no change) when each of the following changes is made: a. adding more N (g) SHIFI RIGHT b. adding more N0 2 (g) SHI FT Lt?FT c. increasing the volume of the reaction flask SHI~T KI~HT d. lowering the temperature SHIFT lef,