Spm Trial 2009 Che Ans Hlsel

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SU1.fT 4541/1 I'PD IHJLU LANGAT, SELAN(;OR TRIAL SI'M 2009.

19,2021.

25. I A

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FOR PAPER 2

Skcma .Jawapan Kcrtas I KilHia PerclliJaan SPM 2009 Isotopes are atoms (o f the samc elemcnt) ,vith the sameDaerah Buill Langat, ScJangor. ",/ncr. '"" number but dirferent numbcr of ncutrons/nucleon

I

ooIII Ikcomcs the

IV correctmcltingTCIll[Jcratnrc fC

n

I------- -..... Time / min- + - - - - - - - - - - t - - - l _ ~ ___ ____________. _

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yestcd allswer MarksFrom zinc to co erZinc is more electropositive than position of zineis higher than copper in the elctrochemical series

allow the movement of the ions through the solution in the

starch, anyone

(c) I (0

tll\! bacteria bCCOlll\!

2 C1\!aning agcn t n reads with the H iOlls ill (lcidicform insoluble long ..:hain filttv acid

blue s o l u ~ o n will fadel blue colour change to colourless ... _number of coppcr(ll) ions in the solution decreases. I'fhecopper ions have been discharge at the electrode by receivingtwo electron to become copper atoms I metal

Cti- + 2e -7 C;._-- ..Zinc

+ 2eand copper arc further apart than zinc and copper inthe electrochemical series therefore greater voltage will beroduced if ma Ilesium is used in lace of zinc

Total

2 3

1

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(b) + Mg - - -+t - - -ti i ; ) T ~ ; : - ; ; ; : : ; ; ; : ; : ; : ; ; ; ; - - ~ : 1 ; i d - o x - i - d a t i ~ ~

time.(i) I Iron (II)+wi O x i d a t ~ J l ~ -

Fe2+ loses electron I oxidation numher of iron increasesto -I 3

+ e

No ested answer4 +1

lime water tllrned -10(ii) I No

- - - - - - - - - -----

carhonate- --- j Io ZnC01

; coldthe gns into lime water

4

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(b)

~ s t e d Answers MarksI2c of reaction UsesExothennic Warm hands and feet i n thecold weather I Lessen theain ofachin muscle 1+1Cold pack Endothennic Reduce the temperature whenhaving fever I reduce pain in

sweUings from sport inginjuries 1 + 1(i) i Use the wind-shields

Place the flame of ethanol close to the copper ClmStir the water constantlyThe copper can is heated directly without using wire gauzeWeigh the lamp and wick instantly before and after the activityCopper CaJ1 is used

(ii) Energy = mcEl= 100 x 4.2 x3 2 13440 J

Number of moles of ethanol = 9.20 = 0.20 mol46

Burning 0.20 mol of ethanol releases 13440 JBurning I mol ofetanol releases = 13440 67200 J 67.2 kJ 10.20The heat of combustion is 67.2 kJ 1(iii)

The heat of combustion of ethanol is higher than methanol 1Ethanol has more carbon and hydrogen atoms per molecule 1More carbon dioxide molecules are formed as product 1More hcat is rdeaseJ during the formation of bonds 1

( c)

II II I[I I In c==c C--HI III II

% of carbon in A_ , ~ _ ~ c _ ' - - ____ X 100%(12 X4 ) + (\ X8)% of carbon in B-'-"":-'-"---'-____ X 100%(12 X 4 )1 (1 X 10)

III

-- _ ( ~ I H 1HI III I[85.7%

82.7%

P c r ( ; e l : t . ~ ! c \ c of - = , ~ ) o [ l ~ n:.ass in Ai_ s ~ - = - _____._Tolal

II 1-1 II I I [ 1 ~ C C -- C [I

I H

I- 1

7 (,

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with tlilitsof graph::c hail

Translcr all pointsDraw a smooth curveRate of readioll

120 s0.25 cmJ s1

graphRale of reaction at 120s (0.11 O.Corrcct answer

increaces

paper)

Th c frequency of the collisions belween the particles illcreasesThe frequcncy of c1Tectivc collisions between the particles in,'..',,,,,"The rate of reaction is higher

is lower

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eupboard. Bactcrial growth II adivily is ~ i o w e r . 1 Bacteria prouuce:; less toxic. 1 Food stored in the lasts longer II Rale of lood

9 (ii) Total hydrogen gas volume (em3)

30

20

10

Time (s)o 30 GO 90 120 ISO 180 210 270

10 11

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-,--':-.'-,---c--f-----:---::-------- _ S ~ g e s t e d Answers

Soft II Easily bentApparatus: Weight, ruler, retort standMaterials: Steel bal!, bronze block, copper blockProcedure:

I. A steel ball is ccllotaped onto the surface of the copperblock_2. A weight of I k g is hung at a height of Im from the steelball.

3. The weight is dropped onto the steel ball.4. The diameter ofthe dent formed on tile:; copper block ismeasured.5. The experiment repeated using the bronze block.

, I Observation:The diameter ofthe dent formed on the copper block is largershows alloy bronze is harder than copper.

(ii) I Explanation:I. The atoms in copper are arranged in an orderly manner

causing the atoms to slide easily.2_ The tin atoms in bronze disrupt the orderly arrangement of

copper atoms.3. Making it difficult for the copper atoms to slide over eachother.

(c) I (i) I S02 + th O -- 7 H2S0] II SO] + H20 H2S0 4ReactantsProduct

(ii) ILowers the pH of water in ponds and liversAquatic life diesIncrease the acidity of the soilPlant diesLeaches the minerals and nutrients of the soil (decreaces thefertility of the soil)Corrodes buildings and metals structures

Total

12

I

Max. 10.111I11

1Max. 5I 20

Answers

I. a)

2

b)

2

o

Rubric~ - - - - - -Able to record all 5 readings with one decimal placeand unit.Answer: 0.0 s 30.0 s 60.0 s 90.0 s 120.0 s

cm} cm) tm 3 6.4 cm) 7.0 cmAble to record all 5 readings correctly without unit anddecimal placeIJ readings correctly with one decimal pl3Cc andunit.

Rubricto construct a suitable table with title and readmgs

with unit.- - - - - ~ - - - -_____ea_dings 1 - - - ~ - _ - - 1 2.2

30.0 4.260.0 5.6

6.4120.0 7.0

Able to construct a tnblc wilh title nr unit with readingReadiI1g:21() 2.2

4.25.6 - - - - - - ~ 6.4

120 7.0Able to construct a table with at least 2 columns and 2

2

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e)

to classify allihe 2 pairs of ions corredly.Answer: i - - s : ; , ~ d ' d m ~ d ' T e . , ___

I IV l' II '--.-l2o

f), Score . - . - ' l i ~ ~ l e to slate the .

AIlswer: (XI' ions are selectively discharged at (I11mleproducing oxygen gas because il ,:, lower lhat 50/ ' ions IIIthe Electrochemical series..IAble to state the iufef(;nee but less accurate.-

. Answer: Ofr ions an: discharged at anode, pro(Juelllg oxygel l,ga,:".AllY suit e s p o l l ~ e

i ions arc d i s c h a f g e d / O x ~ n a r ~ produced .... __re';n"n


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-h) QllestionRubric noAble to calculate the volume, number of mole and ma')s of 2 (a} tAble 10 stale the ; l j ~ ; ' ; of t h ~ experiment correctly]oxygen released at time 120 seconds correctly, Sugessted Answer: ISample answer:Volume of oxygen gas = 4,8 ern] I To dctenninc the positioll of carboll in the reaelivity series ofNo of mole of oxygen g a ~ = 0.0002/2x I0-4 I metals,- ' - ~ - ~ - - - ~ - - - ~ - - Mass of oxygen gas 0.0002 x 32 I [Able to stale the aim of the experiment less correctly]

I Sample answer: I Where is the of carbon in the reactivity series of To determine t ~ o s i t i O l l of carbon.i) [Ab"e to give an i d ~ ; ~ ; [ i j : ; ; : a i ~ l o f t l 1 ~ e x p e r i l 1 l e ~ t J - - Sample answer:The position of carhon,[No r e s p o n s e ~ 1 ! w n ) ! l g ~ ~ p ~ l I 2 ! : ' . e L2(b) [Ahle to state the hypothesisSample answer: If carbon can reduce the metal oxide, then carbon is above the metal in the reactivity scries of metals. - [ A b l ~ t ; : ; ; ; t ; k - the hypothesis l c s - s - c - ( - ) r r - C - ~ c - t - ; - l y - C : ] - Sample answer: If carbon reacts with a metal oxide, carbon is more reactive. j) [Ablc(;;- g i v ~ ; n i d e a of h y p o t h e ~ i s 1---- - Sample answer:Some m e t ~ l oxides react with carbon, _____

~ < ) o I . l : > e or "/rong r e s p o ~ ~ __ ~ _ _ _ _ _(Able to slale all three variables correctly]Score

J

20

Able to predict the changes in mass for electrode R ~ S conclusion correctly.Answer:Electrode R: mass decreasedIElectrode S: mass increa


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Spm Trial 2009 Che Ans Hlsel

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