Transcript
AP Chemistry Chapter 19 Thermodynamics Practice Test Test Multiple Choice Identify the choice that best completes the statement or answers answers the question. question.
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1.
∆G
a. b. c. d. e.
refers to the free-energy f ree-energy change associated with which of the following? the format formation ion of 1 mol of a compound compound from from its its constitu constituent ent elemen elements. ts. the decomposition of 1 mole of a compound into its its constituent elements. elements. the freezi freezing ng of 1 mol mol of of a substa substance nce.. the meltin melting g of 1 mol mol of of a subs substan tance. ce. all all of of th the abo above ve..
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2. Under what conditions conditions can we absolutely say a system system is at equilibrium at constant constant pressure and temperature? temperature? a. ∆ H d. ∆G " ! ! b. ∆ H " ! e. ∆S " " ! c. ∆G !
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#. $hich of the following following substances would you e%pect to have the highest highest entropy at 1 atm of of pressure? a. & '( s)(1 d. !.* mol s)(1 mol) mol of ethano ethanoll in !.* !.* mol of of & '(l '(l ) b. & '(l e. a gaseous '(l )(1 )(1 mol) gaseous solut solution ion of of !.* mol mol of & '( g ) and and !.* !.* mol mol of of +& ( g ) c. & '( g )(1 )(1 mol)
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,. or any isolated spontaneous spontaneous process that is endothermic which of the following conditions are true/ (1) ∆G 0 ! (2) ∆G " ! (#) ∆S 0 ! (,)∆S " ! (*) ∆S 0 ! () ∆S "! a. (1 (#) and (,) d. (1) (,) and () b. (2) (,) and () e. (2) (,) and () c. (1) (1) (,) (,) and and (*) (*)
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*. or which of the following following changes would you you e%pect ∆S to to be less than zero? a. & '(l d. +' ( s) '(l ) → & '( g g ) s) → +' ( g g ) b. +'( g e. 2 4g+l( s) g ) 3' ( g g ) → +' ( g g ) s) → 2 4g( s) s) +l ( g g ) c. 2 5' ( g g ) → 2 5' ( g g ) ' ( g g )
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. $hen 67' dissolves in water at room temperature ∆ H is is positive for the dissolution process. 8iven this information what can you conclude? a. ∆G " ! for the dissolution process. d. ∆S " " ! for the dissolution process. b. ∆G ! for the dissolution process. e. ∆S 0 0 ! for the dissolution process. c. 9he diss dissolv olving ing of of salts salts in wate waterr is alwa always ys a spontaneous process.
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:. $hich of the following following is true for the sublimation sublimation of solid +' at room temperature and pressure? pressure? a. ∆ H and d. ∆G becomes more positive as temperature and ∆S are are positive. increases. b. ∆ H and e. ∆G is positive. and ∆S are are negative. c. ∆ H is is negative and ∆S are are positive.
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;. $hich of the following following can be used to calculate calculate directly the value of an equilibrium equilibrium constant constant for a reaction at a given temperature? a. ∆ H d. ∆G b. ∆ H e. ∆G c. ∆S ° °
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°
<. +alculate ∆G° for the following reaction at 2* °+ , 7'( g ) & '( g ) → * ' ( g) g) + , 7& ( g ) given the following
∆G
values/ values/ 7' ;.:1 =>mol@ =>mol@ & ' −22;.1 22;.1 =>mo =>mol@ l@ ' !.! !.! =>m =>mol@ ol@ 7& −1.
=>mol. a. <*;.2 => b. −21,*.1, => c. 21,*.1, =>
d. −1#1;.1; => e. 1#1;.1; =>
____ 1!. Astimate the normal boiling boiling point for &+l given given the following information/ information/ ∆ H
1.1# =>mol and
a. 1;;C+ b. 1;; 6 c. !.1;molB6
for sodium chloride is the free energy change for which of the d. 7a( s) s) 3+l ( g g ) → 7a+l( s) s) e. 2 7a+l( s) s) → 27a( s) s) +l ( g g )
____ 12. or which of these processes processes is the value of ∆S e%pected e%pected to be negative? D. 7a+l is dissolved in water. DD. 5team condenses to liquid water. DDD. DDD. Eg+' Eg+' is deco decomp mpose osed d into into Eg' Eg' and +' . a. D only d. DDDD and DDD only b. D and DDD only e. D and DD only c. DD only ____ 1#. $hat are the signs of the enthalpy enthalpy change and entropy entropy change for the melting melting of ice? & '( s) s) → & '(l '(l ) 9he signs represent ∆ H ° and ∆S ° respectively. a. d. + − b. − − e. ! ! c. − + ____ 1,. Under which set of conditions conditions does a temperature temperature e%ist at which equilibrium equilibrium can be established established with all reactants and products in standard states? D. ∆S is is ∆ H is is DD. ∆S is is − ∆ H is is − DDD. ∆S is is ∆ H is is − a. D only b. DD only c. DDD only
d. D and DD only e. D and DDD only
____ 1*. $hich of the following following substances is e%pected e%pected to have the largest largest standard molar entropy? entropy? a. & '( s) d. & ' (l ) s) b. & '(l e. & ' ( g ) '(l ) c. & '( g ) ____ 1. Dn which process would would ∆G be e%pected to be positive? a. melting ice at −1!°+ and 1.! atm pressure d. sublimation of dry ice at 2* °+ b. water evaporating at 2* °+ into dry air e. a burn burnin ing g cam campfir pfiree c. coolin cooling g hot hot water water to room room temper temperatu ature re ____ 1:. $hich is not e%pected to have a value of zero? a. ∆ H fo d. for ' ( g g ) b. c.
∆G
e.
for 6( g )
∆ H
fo for Fr (l )
∆G
for '( g )
S for for +a( s) s) at ! 6
____ 1;. $hich process is e%othermic e%othermic and occurs with a decrease decrease in entropy? a. & '(l d. 2 & '(l ) → 2 & ( g '(l ) → & '( s) s) g ) ' ( g g ) b. & '( s) e. & '(l s) → & '(l '(l ) '(l ) → & '( g ) c. & '( s) s) → & '( g ) ____ 1<. Dn order to calculate the entropy entropy change for the following following reaction at 2* °+ and one atmosphere what additional thermodynamic thermodynamic information information is needed? +( s +( s graphite) '2( g g ) G +'2( g g ) a. ∆ H fo for +' ( g g ) b.
∆G
fo for +' ( g g )
c.
∆ H
and ∆G fo for +' ( g g )
d. S ° fo for +' ( g g ) e. ∆ H and ∆G for both +( s s grap graphi hite) te) and ' ( g ) ____ 2!. or a certain reaction ∆ H ° −1*! =>mol and ∆S ° −*! >mol ⋅ 6. $hich of the following statements is true about the reaction? a. Dt is spont spontane aneous ous at at high high temper temperatu atures res only only.. b. Dt is spontaneous at low temperatures only. only. c. Dt is sponta spontaneo neous us at at all all temper temperatu atures res.. d. Dt is nonsp nonspon ontan taneou eouss at all all temper temperatu atures res.. e. 9here is is no temperat temperature ure at which which the reacti reaction on will will reach equil equilibriu ibrium. m. Problem
21. +alculate +alculate the p& of water water at ,!C+ given the the following following informati information on for the equilibr equilibrium ium at 2*C+/ & '(l '(l )
⇔
& (aq) aq)
'& (aq) aq)
∆G
(=>mol)
−2#:.2
!
−1*:.#
∆ H
(=>mol)
−2;*.;
!
−2#!.!
(&int/ Hetermine ∆G and K and K at at ,!°+ to solve for p&.) °
