OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
1
Which row is correct?
Your answer
2
[1]
This question is about trends in the periodic table. Which trend is correct? A
melting point decreases from lithium to carbon
B
boiling point decreases from fluorine to iodine
C
first ionisation energy decreases from lithium to caesium
D
first ionisation energy increases from nitrogen to oxygen
Your answer a nswer
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[1]
OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
3
The table below shows standard enthalpy changes of formation& Cm$"*! - H /
. ml &1
'()'O*+s, -*$$
(!O+g, -!)!
f H.
CO!+g, -*)
What is the enthalpy change for the following reaction? !'()'O*+s, / C+s, 0 !'! +g, / )(!O+g, / CO!+g, A
-$*" 12 mol -#
B
-3)" 12 mol -#
C
/3)" 12 mol -#
D
/$*" 12 mol -#
Your answer
4
[1]
Carbon monoxide reacts with steam in the following reaction equation4 CO+g, / (!O +g,
⇌
CO!+g, / (!+g,
H 5
-)" 12 mol -#
Which change will shift the position of equilibrium to the right hand side of the equation? A
decrease in pressure
B
increase in pressure
C
decrease in temperature
D
increase in temperature
Your answer
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[1]
OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
()
6 student used the apparatus below in an experiment to determine the enthalpy change of combustion of methanol. The student measured #"" cm * and poured it into the bea1er.
The student measured a temperature rise of #".3 7C. The student calculated the amount of energy transferred to the water. Which of the following uses the appropriate number of significant figures and correct standard form to represent the result of the calculation? A
).*8 9 #"* 2
B
).* 9 #"* 2
C
)*. 9 #"! 2
D
))." 9 #"! 2
Your answer
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[1]
OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
()
The student:s calculated enthalpy change was less exothermic than the ;alue in data boo1s. Which of the following errors could ha;e contributed to this result? +rrr 1
6fter the final temperature was recorded& the student remo;ed the burner from under the bea1er. The flame burnt for a further 3 minutes before weighing the spirit burner.
+rrr 2
The student recorded the final temperature 3 minutes after remo;ing the burner.
+rrr 3
The student spilt some water on the bench when pouring the water from the measuring cylinder into the bea1er.
A
#& ! and *
B
Only # and !
C
Only ! and *
D
Only #
Your answer
[1]
escribe and explain how electrical conducti;ity occurs in mercury+ II, bromide and mercury& in both solid and molten states. .. []
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OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
()
=romine reacts with iodine to form iodine monobromide& I=r. The table below lists some a;erage bond enthalpies which are required in different parts of this question.
(i)
6;erage bond enthalpy is the enthalpy change for the brea1ing of # mole of bonds in gaseous molecules. Why do =r ! and I! not exist in the gaseous state under standard conditions? .
(ii)
Calculate the enthalpy change of formation&
f H&
for I=r.
f H 5
()
[1]
12 mol@#
[2]
=romine disproportionates when it reacts with potassium hydroxide solution. Auggest an equation for this reaction.
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[1]
OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
6 mixture of '! and (! was left to react until it reached equilibrium. The equilibrium mixture had the following composition4 '! #.!" mol dm @* (! !."" mol dm @* '(* ".8BB mol dm@* Calculate a ;alue for K c for this equilibrium.
K c 5 dm$ mol@!
5
[3]
Atudents wor1 together in groups to identify four different solutions. ach solution contains one of the following compounds4 D
ammonium sulfate& +'(),!AO)
D
sodium sulfate& 'a!AO)
D
sodium chloride& 'aCl
D
potassium bromide& E=r
Your group has been pro;ided with uni;ersal indicator paper and the following test reagents4 D
barium chloride solution
D
sil;er nitrate solution
D
dilute ammonia solution
D
sodium hydroxide solution.
6"esti* 5 %*ti*"e! * *e7t $,e
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OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
6 student in your group suggests the following plan4 D
6dd about # cm depth of each solution into separate testFtubes.
D
6dd a few drops of barium chloride solution to each testFtube.
D
6 white precipitate will show which solutions contain sulfate ions.
D
Two of the solutions will form a white precipitate
>escribe how you would expand this plan so that all four solutions could be identified using a positi;e test result. You should pro;ide obser;ations and conclusions that would enable your group to identify all four solutions. .. .. .. .. .. .. .. .. .. .. .. .. .. ..
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OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
10
Complete the table below to show where antimony is found in the %eriodic Table.
'eri!
Bl%.
[1]
Silicon dioxide, SiO 2, has the same structure and bonding as 11 diamond. State the structure and bonding in SiO 2.
..........................................................................................................................
..................................................................................................................... [1]
12
(i)
Complete the electron configuration of a bromide ion. #s! ..................................................................................................... [1]
(ii)
6 student adds a small ;olume of aqueous sil;er nitrate to an aqueous solution of bromide ions in a testFtube. The student then adds a similar ;olume of dilute aqueous ammonia to the same testFtube. >escribe what the student would see in the testFtube after the addition of aqueous ammonia. .........................................................................................................
(iii)
[1]
Write an ionic equation for any precipitation reaction which occurs in the student:s tests. Gnclude state symbols. ............................................................................................................ [1]
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OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
13
6 chemist carries out reactions of barium and barium nitride& =a*'!. Re%ti* 1 =arium is reacted with water. Re%ti* 2 =arium nitride is reacted with water& forming an al1aline solution and an al1aline gas. Re%ti* 3 =arium is reacted with an excess of oxygen at 3""7C& forming barium peroxide& =aO !. Write equations for Re%ti* 1 and Re%ti* 28 Ggnore state symbols. eaction #4 ............................................................................................. eaction !4 ....................................................................................... [3]
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OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
14
(ydrogen iodide& ( I& is a colourless gas that can be made from the reaction of hydrogen& (!& and iodine& I!. This re;ersible reaction is shown in e9"iliri"m 381 below. (!+g, / G!+g,
⇌
!(I+g,
The acti;ation energy for the forward reaction is #B* 12 mol -#. ()
Complete the enthalpy profile diagram below for the forward reaction in equilibrium *.#. On your diagram4 D
Habel the acti;ation energy& E a
D
Habel the enthalpy change of reaction& H
D
Gnclude the formulae of the reactants and products.
[2]
()
Calculate the acti;ation energy& E a& for the re;erse reaction.
E a +re;erse reaction, 5 ............................................ 12 mol@# [1]
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OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
'rt (%) is * the *e7t $,e
(%)
When the re;erse reaction ta1es place hydrogen iodide& ( I& decomposes to form iodine and hydrogen. Calculate the enthalpy change when **$ dm * of hydrogen iodide& measured at room temperature and pressure& decomposes. Gnclude the sign for enthalpy change in your answer.
enthalpy change .................................................... 12 [2]
1
This question is about the determination of enthalpy changes. ()
6 student carries out an experiment to find the enthalpy change of reaction& H r& for the reaction below. 'a!CO*+s, / !(Cl +aq,
!'aCl +aq, / CO!+g, / (!O+l,
Gn the experiment& *.#8 g of 'a !CO* are added to 3"." g of !."" mol dm @* (Cl & an excess. The temperature of the reaction mixture increases by 3.3 7C. Calculate
H r&
in 12 mol@#.
Ii;e your answer to three significant figures. The specific heat capacity& c & of the reaction mixture is ).#8 2 g@# E@#.
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OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
H r 5
........................................... 12 mol@# [4]
'rt () is * the *e7t $,e ()
The booster roc1et of a spacecraft uses a mixture of aluminium and ammonium chlorate+ VII,& '()Cl O)& as a fuel. The equation and some enthalpy changes are shown below.
*6l +s, / *'()Cl O)+s,
(i)
6l !O*+s, / 6l Cl *+s, / $(!O+g, / *'O+g,
H 5
-!$BB 12 mol @#
What is meant by the term standard enthalpy change of formation? Ii;e the standard conditions. ................................................................................................................. ................................................................................................................. ................................................................................................................. ................................................................................................................. ............................................................................................................ [3]
(ii)
Write the equation& including state symbols& for the reaction that represents the standard enthalpy change of formation of '( )Cl O)+s,. ............................................................................................................ [2]
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OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
1
eaction rates can be increased or decreased by changing conditions of temperature and pressure. (i)
xplain how increasing the temperature increases the rate of reaction. Gnclude a labelled s1etch of the =oltJmann distribution& on the grid below. Habel the axes.
.......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .................................................................................................................... [4] (ii)
>escribe and explain the effect of decreasing the pressure on the rate of a reaction. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ................................................................................................................... [2]
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OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
[#tl Mr.s 2]
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OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
A*s:er
'rt Mr.s *! ;"i!*%e
6"esti* S"r%e *! #$i% Q4-GCE-Chemistry A-Specimen-
C
The %eriodic Table& Iroup !& halogens Q6-GCE-Chemistry A-Specimen-
C
The %eriodic Table& %eriodicit Q11-GCE-Chemistry A-Specimen
A
%hysical Chemistry& nthalpy Q12-GCE-Chemistry A-Specime
C
%hysical Chemistry& Chemical quilibrium Q18(a-GCE-Chemistry A-Speci H032/01
B
%hysical Chemistry& %ractical nthalpy Changes& 6nalysis Q18(!-GCE-Chemistry A-Speci H032/01
B
%hysical Chemistry& %ractical nthalpy Changes& ;aluatio (g=r ! conducts when molten but not when solid ✓
xplanations m"st be included for !nd and *rd mar1s.
because ions are mobile in molten (g=r ! ✓
Q20("-GCE-Chemistry A-Speci H032/01
The %eriodic Table& %eriodicit
<;=OR+ references to aqueous (g=r ! but are fixed in a lattice in solid (g=r ! ✓ <;=OR+ Kdelocalised ions: O Kfree ions: for Kmobile ions: DO =O# ALLO> any mention of electrons mo;ing
+because energy is needed to brea1, induced dipole-dipole interactions L Hondon forces between molecules ✓
DO =O# ALLO> any mention of / ions mo;ing ALLO> forces of attraction between molecules OR ;an der Waals: forces <;=OR+ reference to strong or wea1
E=r / E=rO / (!O ✓
xpression4 K c 5 N'(*! L N(!*N'! ✓
The %eriodic Table& %hysical The (alogens& nthalpy Cha ALLO> *=r ! / $EO( 3E=r / E=rO* / *(!O ALLO> ionic equation Aquare brac1ets required
Q1("-GCE-Chemistry A-Specim
The %eriodic Table& The (alo Q3(!(i-GCE-Chemistry A-Speci H032/02
%hysical Chemistry& Chemical quilibrium
Calculation4 5 +".8BB,!L+!."",*+#.!", ✓ 5 "."8"# ✓ +dm$ mol@!, ALLO> from # sig fig up to calculator display Correct answer alone scores all mar1s
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The %eriodic Table& %hysical The (alogens& nthalpy Cha Q1(!(ii-GCE-Chemistry A-Speci H032/02
=ond brea1ing +/#*, / +/#3#, 5 +/,*)) =r ! / !EO(
M#+b,+i,FICFChemistry 6FApeci ("*!L"!
%age #3
OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
A*s:er
'rt Mr.s *! ;"i!*%e
6"esti* S"r%e *! #$i%
#$ease re%er t& the mar'in instr)cti&ns &n pae 4 &% this mar' scheme %&r )i"ance &n h&* t& mar' this +)esti&n,
<*!i%tive s%ie*ti-i% $i*ts my i*%l"!e
Q4(a-GCE-Chemistry A-Specim
Level 3 (& mr.s) >escribes full details of all of the test procedures and obser;ations that allows all four compounds identified There is a wellFde;eloped line of reasoning and the method is clear and logically structured. The information presented is rele;ant and substantiated by obser;ations from the tests described. Level 2 (3&4 mr.s) >escribes most of the tests in some detail including the obser;ations that allows all four compounds to be identified. There is a line of reasoning presented and the method has some structure. The information presented is in the mostFpart rele;ant and supported by some e;idence of obser;ations from the tests described. Level 1 (1&2 mr.s) >escribes some of the tests but lac1s details and obser;ations to allow the identification of all four compounds
Detils - tests To identify sulfates4 D 6mmonium ion test4 on the sulfates already identifiedP warm with 'aO(+aq, followed by D Qni;ersal indicator test4 use of moist indicator paper on +ammonia, gasP correct obser;ation +al1aline gasLhigh p(Lblue or purple, for identification of +'(),!AO)& and by default of 'a!AO).
The %eriodic Table& %ractical Mualitati;e analysis& %lanning
To identify halides4 D (alide ion test4 addition of sil;er nitrate solution to remaining two solutionsP correct obser;ation +white precipitateLcream precipitate, followed by D Aolubility of precipitate4 addition of dilute ammonia solution to halide precipitatesP correct obser;ation +sil;er chloride dissol;es, enabling identification of 'aC$ and by default of E=r.
The information is basic and the method lac1s structure. The information is supported by limited e;idence of the obser;ations& the relationship to the e;idence may not be clear. " mar1s 'o response or no response worthy of credit. period 5 3 6'> bloc1 5 p ✓
Q1(a-GCE-Chemistry A-)ne 20
The %eriodic Table& %eriodicit Iiant co;alent +lattice, ✓
6g +aq, / =r +aq, 6g=r+s, ✓
ALLO> KIiant lattice with co;alent bonds: ALLO> KIiant co;alent bonds: <;=OR+ K Iiant molecular: or Kmacromolecular: DO =O# ALLO> KCo;alent bonds between molecules: ALLO> ... )s! *d#")p$ ALLO> subscripts A=D *> <;=OR+ #s! seen twice ALLO> solid OR ppt for precipitate <;=OR+ Kdoes not dissol;e: O Kpartially dissol;es: quation A=D state symbols required
Re%ti* 1 =a / !(!O
Ggnore state symbols
+#s!, !s! !p$ *s! *p$ *d#" )s! )p$
✓
Cream A=D precipitate ✓
/
-
Q4(c -GCE-Chemistry A-)ne 2 .321/01
The %eriodic Table& %eriodicit
Q(!(i-GCE-Chemistry A-)ne .321/01
The %eriodic Table& The (alo Q(!(ii-GCE-Chemistry A-)ne .321/01
The %eriodic Table& The (alo Q(!(iii-GCE-Chemistry A-)ne .321/01
The %eriodic Table& The (alo
Re%ti* 2 =a*'! / $(!O Correct products ✓ =alancing ✓
=a+O(,! / (! ✓ *=a+O(,! / !'(*
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Q6(c (i-GCE-Chemistry A-)ne .321/01
The %eriodic Table& Iroup !
OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
A*s:er
'rt Mr.s *! ;"i!*%e
6"esti* S"r%e *! #$i%
#here re 3 mr.i*, $i*ts re9"ire! -r 2 mr.s
A==O#A#+ A=S>+R ><#H #
Q3(a-GCE-Chemistry A-)ne 20
%hysical Chemistry& nthalpy
<;=OR+ state symbols. E a4
ALLO> +/,#B* only as an alternati;e label for E a ALLO> no arrowhead or arrowheads at both ends of acti;ation energy line The E a line must point to maximum +or near to the maximum, on the cur;e OR span approximately 8"S of the distance between reactants and maximum regardless of position ALLO> 6 or 6 for E a @H G there is no RH labelled 6HHOW - as an alternati;e label for RH . < RH is labelled <;=OR+ any numerical ;alue.
(! and I! on H(A A=D !(I on (A A=D correctly labelled E a ✓
RH labelled with product below reactant A=D arrow downwards ✓ +/,#8! ✓
DO =O# ALLO> -RH . ALLO> this arrow e;en if it has a small gap at the top and bottom i.e. does not quite reach reactant or product line This is the O=L acceptable answer
Q3(!-GCE-Chemistry A-)ne 20
%hysical Chemistry& nthalpy L. t *s:er i- 3 . A>ARD 2 mr.s <- 3 (* si,*) OR3 (i*%rre%t si,*) A>ARD 1 mr.
ALLO> one mar1 for /#!$ 12
'o of moles of (I 5 #) moles ✓ nthalpy Change 5 /$* 12 ✓
Aign and ;alue required. ALLO> C from incorrect number of moles of (G A==O#A#+ A=S>+R ><#H #
+R O= A=S>+R L<=+ < *s:er F &383 (. ml1) :r! 4 mr.s < *s:er F ()383 (. ml1) :r! 3 mr.s (i*%rre%t si,*) < *s:er F 3E300 (. ml1) :r! 3 mr.s ("se! i*ste! - .)8 +*er,y + calculated correctly 5 ##).3+2, ✓ O #.#)3 +12, ✓ Mles 6mount& n& of 'a!CO* calculated correctly5 "."*+"", ✓ Cl%"lti*, GH correctly calculates UH in 12 mol F# to * or more sig figs ✓ R"*!i*, *! Si,* calculated ;alue of UH rounded to * sig. fig. with minus sign✓
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Q3(c -GCE-Chemistry A-)ne 2 .322/01
%hysical Chemistry& nthalpy
'ote4 + 5 3"." 9 ).#8 9 3.3 ALLO> ##).3 O correctly rounded to * sig figs +2, <;=OR+ sign <;=OR+ wor1ing ALLO> 3*.#8 9 ).#8 9 3.3 OR #!!!.$"8! OR #!!" OR correctly rounded to * or more sig figs in 2 or 12 <;=OR+ wor1ing <;=OR+ trailing Jeros <;=OR+ sign at this intermediate stage ALLO> C from incorrect q andLor incorrect n inal answer must ha;e correct sign and three sig figs ALLO> -)".8 12 mol -# if 3*.#8 used in calculation of q ALLO> -)".B 12 mol -# if + is rounded to #!!" from 3*.#8 earlier
Q4(a-GCE-Chemistry A-)ne 20
%hysical Chemistry& nthalpy
OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
A*s:er
'rt Mr.s *! ;"i!*%e
6"esti* S"r%e *! #$i%
+nthalpy change, when one mole of a compound ✓
ALLO> energy required OR energy released ALLO> one mole of substance OR one mole of product DO =O# ALLO> one mole of element
Q4(!(i-GCE-Chemistry A-)ne .322/01
is formed from its elements ✓
%hysical Chemistry& nthalpy
!8 E L !3 7C A=D # atm L #"" 1%a L #"# 1%a L # bar ✓ <;=OR+ reference to concentration V'!+g, / !(!+g, / VC$ !+g, / !O!+g,
Q4(!(ii-GCE-Chemistry A-)ne .322/01
'()C$ O)+s,
%hysical Chemistry& nthalpy
correct species ✓ Se%*! mr. %* *ly e :r!e! i- ll s$e%ies i* the e9"ti* re %rre%t
correct state symbols and balancing ✓
DO =O# ALLO> multiples of this equation A==O#A#+ A=S>+R ><#H #
Candidates do not need E a on graph
ALLO> particles instead of molecules on the y axis DO =O# ALLO> atoms instead of particlesLmolecules ALLO> +C for the incorrect use of atoms +instead of moleculesLparticles, DO =O# ALLO> enthalpy on the xFaxis axes labelled +number of, molecules and +1inetic, energy ✓
Correct drawing of a two =oltJmann distributions i.e. both cur;es must start within the first small square nearest to the origin A=D must not touch the x axis at high energy ✓
>rawing of =oltJmann distribution at two di fferent temperatures with higher and lower temperature clearly identified + ie T!T#, ✓
6>C F +6t a higher temperature, more molecules ha;e energy abo;e acti;ation energy OR greater area under the cur;e abo;e the acti;ation energy ✓
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DO =O# ALLO> increase of more than one small square at high energy end of cur;e.
DO =O# ALLO> lower acti;ation energy 6>C requires more molecules ha;e or exceed acti;ation energyLE a. <;=OR+ more molecules ha;e enough energy to react for the 6>C mar1 +as not lin1ed to E a, ORA if states the effect when the temperature is lower <;=OR+ +more, successful collisions
Q6(a(i-GCE-Chemistry A-)ne .322/01
%hysical Chemistry& eaction
OCR AS/A Level Chemistry A (H032/H432) M!"le 3 #$i% #est & 'eri!i% #le *! +*er,y
A*s:er
'rt Mr.s *! ;"i!*%e
6"esti* S"r%e *! #$i%
+>ecreasing the pressure, decreases the rate of reaction
Crre%t e--e%t * rte m"st e li*.e! t res* -r the -irst mr.i*, $i*t8
Q6(a(ii-GCE-Chemistry A-)ne .322/01
A=D >ecreased concentration of molecules OR 'umber of molecules remains the same but the ;olume increases OR Hess molecules per +unit, ;olume ✓
%hysical Chemistry& eaction
ALLO> molecules are further apart <;=OR+ less crowded ALLO> particles or atoms for molecules ALLO> Kspace: for ;olume DO =O# ALLO> area instead of ;olume ALLO> collisions occur less often OR decreased rate of collision <;=OR+ less chance of collisions
Hess -re9"e*t collisions ✓
Kless collisions: alone is not sufficient <;=OR+ successful
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