kertas 2 pep percubaan spm johor 2008
TRANSCRIPT
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8/12/2019 Kertas 2 Pep Percubaan SPM Johor 2008
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QuestionNo.
Explaration Mark X Mark
2(a)
(b )
(D(iD
(c)
(d) (D
(iiD
(e)
(0
Tsa represenktion f a chemical ubstance sing ertersfor atoms and subscripts or each ype of atoms presentin the substance.
I Able to name suitable acid and metal and its equationFor exampleHydrochloric acid and zinc metalZ n + 2 H C l ) Z n C l 2 + L I 2
Hydrogen gas must be flowed/through/into hecombustion ube for a few minutes before heating/
The flow o1'hydrogen as must be continuous hroughoutthe experimenVI Accept any one answer]
Number of mole of copper i.6264
'0 .0 2 5 m o 1 e
Number of mole of oxygen = 0.40
t b: 0 . 0 2 5 m o 1 e
Numper of mole of copper Number of mole of oxygen0.025 : 0.025
The simplest atio 1 : 1
'I'he empirical ormula of copper(Il) oxide is CuO
Iron(II) oxide / Tin(II) oxide / Lead(II) oxide
Burning of metal n exccss .xygen
Total marks
I
I1
1
I
I
I
I
I
r0
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QuestionNo.
Explanation MK I Mark
3 (aX0(ii)
(bXD(iD
c( i)(iD
d(D(iD
Group 1G
and Period 4
DzLSoluble n water// high melting / boiling poinV/ conductselectricity n molten or aqueous olution
EThe nuclei attraction owards he valence electrons sweaker n E.'I'hus it is easier or E to lose release n electron oform a positively charged on.
L//MCovalent bond
Total Marks
1 +1
1
I
1
1
I
1i
10
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QuestionNo.
Explanation Ivlark X Mark
4 (a)
(b)
(c)
(d)
(e)
(r)(e) i)
(iD
A weakacid s an acid hat dissociates artially nwater o produce ydrogen ons
ISour I t
IColourlesso pink
It
Neutralisations an exothermiceaction./eleases eatI
1
Some ofthe energy produced during the reaction Ibetween a weak acid and strong base s used o Iionise/dissociate ompletely he weak acid molecules. I t
H - + O H - t I - I 2 O I IINumber of moles of malic acid= )=Q0 I
= 'oo,r,", I tI
Number fmoles fsodium ydroxide sed I:2.00 x 17.30 |looo ]:
0.0746 ol iI
I1 mble of H* reacts with 1 mole of OH- lThuS. number of mole of H+ ions I
I in the sample 0.0746 I tl l] . O.O:Z+mote of
malic acid produces 0.0746 mole ofI
Lnydrogen on. II Hence, mole of malic acid produces .0J46 iI o.orz: ll ^
:2moleof r fI
'
l o '| ilo rf -of" of malic,acid No^ofmole of NaoH ]l 1 : 2 II Therefore, alicacid
s diprotic proven) i
] total ma4r ] 10
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QuestionNo.
t rw nl onot inn Mark X Mark
sa(i)
(iD
(iiD
(b)
(c)(i)
(iD
Haber Prooess
3 H2 +N2 )2 NH:
Catalyst IronTemperature 450oC
Sulphur rioxide is dissolved n concentrated zSQ+
tolorm oloum
Oleum s diluted with water o produce sulphuric acid
(NH+)zSO+
% o f N:4 D x 1 0 0 %132
: 21.21vo
Total marks
I
1 lI
I
l l
r l1 lI
1
11
l0
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QuestionNo.
Explanation Mark I Mark
6(aXD
(iD
Ethanol
One mole of ethanol when completely bumt in oxygen(undcr standard onditions) will release 260 kJ ofheatenergy
No of moles of alcohol 0.23 46: 0.005 mo l
I nrolot alcohol burnt eleased f60 kJThus, 0.005 mol ofalcohol burnt eleased .3 kJ
mca: 6,3 kJMcs: 6.3 x 1000
6 : 6 3 0 0 / 2 0 O x 4 . 2= 7 . s "C
(bXD
(il)
(cJ Heat s lost to the sunounding / Heat s absorbed ythe apparatus r containers / Incomplete combustion
(d)
C z H s O H + 3 0 2A F i : - 1260
KJMOI
I Reaction athI Lub"l "n".gy -d diagram as 2 different energy evels
IBalanced hemical quation
(e) I - 2656 Jmorr / 2500-2700 Jmofl
Total marks
I
I
I
I
I
I
1
I1
I
10
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QuestionNo.
Explanation Mark I Mark
8 (aXD
(b) D
(ii)
Correct apparatus et upCorrect abelling
Volume of gas cmr
Time/min
Curvelabelf ng a.xes ith units
CaCOr + 2IlCl * CaClz
No. of moles cid (0.1)(50) =1000
1I
I+ CO: + HzO
5 x 10-3
2 mol of I'ICI reaated evolve I mol of COz0.005 mol of HCI reacted volve0.005 mol of COz
2=
0.0025mol COzVolume f CC, (0.0025X24)= 0.05dm'= 60 cm"
Overall average ate ofreaction =Total volume of COzTotal time
= 60 cm3300 s
= 0 . 2 c m 3 s l
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cool and crystals of zinc sulphate re formed.The zinc sulphate rystals are filtered and hen driedbetween sheets f filter papers.The equarion or lhc rcaction s:ZnO + H2SOa---+ nSOa+ ll2O(accept procedures n active voice)
II t 0
Total marks 20
QuestionNo.
Explanation Mark I Mark
10 a)I
Chemical quations tt and IIII Reasons Involving oxidation and reduction occurring] simultaneously/at he same imeI Reaction I
Oxidation: Cu loses electron o form Cu:*I Reduction: Ag- gain electron o form Ag
// Electron ransfbr rom Cu to Ag*or
I O,.idution, Zn ioses electron o form Zn2'I ^ ,] Reduction: H' gainelecnon o form H;l o rI Oxidation: Oxidation number of Zn increase rom 0 to 2+] Reduction: Oxidation number of Ff decrsase rom +l to 0I i/ Eleotron ransfer rom Znto H+
I(bxi) j Bromine ater
Oxidation number of Ag' decrease rom +1 to 0
Terminal Half- Observationnegative F e t * ) F e j * + e Green o brown/yellow
positive B r 2 2 s ) 2 Br- bro$.n o colourless/decolourises
(iD
t + l
I
l + 1
Max 6
il
l + l
1
l + l
I +1
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Draw out I cm' of the solution rom terminal nesative nto atest ube.Add NaOH / NH3 solution
Potassium {exanocyanofenzte(Il) solution o the test ubeObservation: Brown ppt / brown ppt / dark blue pptrespectively.Shows hat iron(il) ion is changed oxidised o iron(Il) ion
[ -l if students does not construct a table ]
Electrolytic Cells Chemicals CellsEnergychange
Electrical energy) Chemicalenergy
Chemical Energy) ElectricalEnergy
Half-equationat anooe Cu I Cu'- + 2e Zn l Zn"' + 2eElectron low Electrons low
Iiom anode ocathode.
Electrons low fromzinc to copper ./
l + l
1 + 1
1 + l