kertas 2 pep percubaan spm johor 2008

8/12/2019 Kertas 2 Pep Percubaan SPM Johor 2008

1/12


2/12

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


3/12

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


4/12

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


5/12

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


6/12

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


7/12


8/12

QuestionNo.


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


9/12


10/12


11/12

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.


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


12/12

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

kertas 2 pep percubaan spm johor 2008

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