SPM Percubaan 2007 SBP Chemistry Marking Scheme

8/14/2019 SPM Percubaan 2007 SBP Chemistry Marking Scheme

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SULIT 4541/1/2/34541/1

Kimia

Kertas 1

Ogos

2007

BAHAGIAN SEKOLAH

KEMENTERIAN PELAJARAN MALAYSIA______________________________________________

PEPERIKSAAN PERCUBAAN SPM 2007

KIMIA

Peraturan pemarkahan Kertas 1, 2 dan 3


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Peraturan pemarkahan ini mengandungi halaman bercetak.

Kertas 1

1 A 21 B 41 A

2 B 22 D 42 A

3 A 23 D 43 C4 B 24 C 44 B

5 B 25 B 45 B

6 C 26 C 46 B

7 D 27 D 47 B

8 A 28 A 48 A

9 B 29 D 49 C

10 C 30 A 50 B

11 B 31 B

12 A 32 C

13 A 33 C14 A 34 B

15 A 35 D

16 D 36 A

17 D 37 A

18 D 38 C

19 B 39 A

20 C 40 C

2


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Kertas 2-Bahagian A

No. Rubric Mark

1 (a)

(b)

(c)

(d)

(e)

P: liquid

S: solid

1. Particles of Q held together by weak intermolecular forces

2. A small amount of heat energy is required to overcome

Diagram

1. label

2. functional apparatus

1. label of axis2. shape of graph

1

1

1

1

1

1

1

119

2 (a)(i)

(ii)

(b)

(c)

(d)

(e)(i)

2.8.3

F+3

A,D,C,B,G,F,E

Atom A has a stable/duplet electron arrangement/2 valance electron

1. Size of atom D is smaller than G2. Strength of the nucleus of atom D to attract electron increase

Ionic

1

1

1

1

11

1

3

Timemin

Temperature /


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(e)(ii)

(e) (iii)

1. Number of shells and electrons2. Charge

- has high melting point and boiling point

- conduct electricity in molten state or aqueous solution- soluble in water

- insoluble in organic solvent

(Any one)

11

1...10

3 (a)

(b) (i)(ii)

(iii)

(iv)

(c) (i)

(ii)

(iii)(iv)

(d)

H+ , Cu+2

Copper electode becomes thicker//brown solid is deposited

Cu+2 + 2e Cu

Copper

Oxygen

(from zinc plate to copper plate)

Oxidation

0 to +2Increases

Zn + Cu+2 Cu + Zn+2

1

11

1

1

1

1

11

1...10

4 (a)(b) (i)

(ii)

(c) (i)

(ii)

Boron oxideTin

1. The presence of tin atoms of different size from the atoms of

copper distrupts the orderly arrangements of copper atoms

2. This prevents the layers of atoms from sliding over one anothereasily

H Cl| |

C == C

| |H H

Does not corrode

11

1

1

1

1

4

-

D

-

DE

2+

x


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(d)

(e) (i)

(ii)

Reinforced concrete

2NH3 + H2SO4 (NH4)2SO4//

2NH4OH + H2SO4 (NH4)2SO4 + 2H2O

% N in CO(NH2)2 = %67.46%10060

)14(2=

% N in (NH4)2SO4 = %21.21100132

)14(2=

Urea has higher percentage of nitrogen so it is more suitable for the

growth of plants

1

1

1

1

111

5 (a)

(b)(i)

(ii)

(c)(i)

(ii)

(d)(i)

(ii)

J: alkeneK: alcohol

Butan-2-ol

Hydration/addition of steam

Orange to green

C3H7COOH

C4H8 + 6O2

4CO2 + 4H2O

No of mole C4H8 =)1(8)12(4

6.5

+

=56

6.5

= 0.1

1 mole of C4H8 4 mole CO2

0.1 mole of C4H8 0.4 mole CO2

Volume of CO2 = 0.4(24)

= 9.6 dm

3

/ 9600 cm

3

11

1

1

1

1

1

1

1

110

6 (a)

(b)(i)

Reduce heat released to the surrounding

Heat change = 200 x 4.2 x 13

= 10920 J

1

1

5


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(b)(ii)

(c)

(d)

(e)(i)

(ii)

Mole of H+/OH-/water = 100 x 2.0 // 0.2 mol

1000Heat of displacement = - 10920 J // -54.6 kJmol-1

0.2 mol

1. Label the energy axis & correct energy level of the reactants andproduct

2. Correct chemical equation// ionic equation

Heat released/ produced when 1 mol of water is formed

decreases

1. Ethanoic acid is a weak acid

2. Some of the heat given out during the neutralization is used to

ionize/dissociate the ethanoic acid

1

1

1

1

1

1

1

110

6

H+ + OH-

H O

Energy


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Essay

No. Rubric Mark

7 (a) 1. pH value of ethanoic acid is higher than nitric acid

2. ethanoic acid is a weak acid; nitric acid is a strong acid

3. ethanoic acid ionises partially in water to produce lowerconcentration of hydrogen ion

4. nitric acid ionises completely in water to produce higher

concentration of hydrogen ion

1

1

1

14

(b) 1. ammonia exist as molecule in chloroform2. there are no hydroxide ions present; the solution is not alkaline

3. when ammonia ionises partially in water to produce hydroxide ion

4. NH3 + H2O NH4+ + OH-

5. the presence of OH- ions makes the solution alkali

11

1

115

(c) 1. Pour [20-100]cm3 of zinc nitrate solution [0.1-1.0]mol dm-3 into a

beaker

2. Add [20-100]cm3 of sodium carbonate solution [0.1-1.0]mol dm-33. Stir and filter the mixture

4. Pour [20-100]cm3 dilute/[0.1-1.0]mol dm-3 sulphuric acid into a

beaker5. Add the residue/precipitate into the acid until in excess

6. Stir and filter the mixture

7. Heat the filterate until saturated/1/3 of original volume

8. Cool the saturated solution9. Filter and dry the crystal

10. Zn(NO3)2 + Na2CO3 ZnCO3 + 2NaNO3

11. ZnCO3 + H2SO4 ZnSO4 + H2O + CO2

1

11

1

1

1

1

11

11...11

20

7


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No. Rubric Mark

8 (a) Formula that shows the simplest ratio of the number of atoms for

each element in the compound. 11

(b)

Empirical formula : CH

RMM of (CH)n = 78

[ 12 + 1]n = 78

13 n = 78

n = 6Molecular formula : C6H6

1

1

1

1

15

(c) Procedure:

1. Clean magnesium ribbon with sand paper2. Weigh crucible and its lid

3. Put magnesium ribbon into the crucible and weigh the crucible

with its lid4. Heat strongly the crucible without its lid

5. Cover the crucible when the magnesium starts to burn and

lift/raise the lid a little at intervals

6. Remove the lid when the magnesium burnt completely7. Heat strongly the crucible for a few minutes

8. Cool and weigh the crucible with its lid and the content

9. Repeat the processes of heating, cooling and weighing until aconstant mass is obtained

10. Record all the mass

Results:

Mass/g

Crucible + lid x

Crucible + lid + magnesium y

Crucible + lid + magnesium oxide z

Calculations:

11

1

1

1

11

1

1

1

1

8

Element C H

Mass (%) 92.3 7.7

Number of

moles 12

3.92= 7.7

1

7.7= 7.7

Ratio of moles 1 1


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Empirical formula: MgaOb / MgO

1

1

1...14

20

No. Rubric Mark

9 (a) 1. Oxidation - increase in oxidation number

2. Reduction decrease in oxidation number

1

12

(b)(i) 1. Fe+2 Fe+3 + e

2. Br 2 + 2e 2Br

3. Iron(II) ions lose electrons to become iron(III) ions. Iron(II) ions

are oxidised

4. Bromine molecules gain electrons to form bromide ions.Bromine molecules are reduced

(a: any suitable reducing agent)

1. Fe+3 + e Fe+2

2. Zn Zn+2 + 2e

3. Iron(III) ions gain electrons to become iron(II) ions. Iron(III)

ions are reduced4. Zinc atoms lose electrons to form zinc ions. Zinc atoms are

oxidised(a: any suitable reducing agent)

11

1

1

1

1

1

18

9

Element Mg O

Mass (g) y-x z-y

Number of moles

24

xy

16

yz

Simplest ratio of moles a b


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(c) Diagram:1. label

2. functional apparatus

Procedure:

1. Pour dilute sulphuric acid into a U-tube

2. Using a dropper, add iron(II) sulphate solutionat one side

3. and acidified potassium manganate(VII) solution at another side4. Place carbon electrode in each side of the U-tube

5. Connect the electrodes to a galvanometer by using connecting

wires//Complete the external circuit

6. Record any change that can be observed after a few minutes

Observations:The green colour of iron(II) solution turns to brown

The purple colour of acidified potassium manganate(VII) solution is

decolourised/change to colourless

(a: any suitable cell)

1

1

1

1

11

1

1

1

110

20

No. Rubric Mark

10 (a) (i)

Catalyst is a substance that changes the rate of a chemical reaction. 1

(a) (ii) - does not change the amount of product formed.

- unchanged chemically at the end of reaction.

- the amount of catalyst is the same before and after the reaction.

- it is specific for a reaction.- only small amount is needed to catalyze a reaction.

- less effective when there are impurerities.

- most of the catalyst are transition metals or their compound.(Any two)

1

12

(a) (iii) - Haber process: iron filling

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- Contact process: vanadium(V) oxide

- Ostwald process: platinum(Any one)

11

(b) 1 Size of reactant

- size of reactant decrease, total surface area exsposed for collisionbetween the particles reactants increase

- frequency of collision between particles increase

- frequency of affective collision increaserate of reaction increase

2 Concentration of reactant- concentration of a solution increase, number of particles per unit

volume increase

- frequency of collision between particles increase

- frequency of affective collision increaserate of reaction increase

3 Temperature of reaction

- temperature of reactants increase, kinetic energy of particles

reactants increase

- frequency of collision between particles increase- frequency of affective collision increase

rate of reaction increase

(Any two)

1

1

1

14

11

1

14

1

1

114

(c) 1 Cooking of solid food

- solid food cut into small piece

- total surface area exsposed to heat increase- food cook faster

2 Cooking of food in a pressure cooker

- high pressure raises the boiling point of water.- cooking is carried out at a temperature higher than 100 o C.

- food cook faster.

3 Storing of food in a refrigerator- temperature in refrigerator is lower

- microorganisms inactive- slow down rate of food decaying

(Any two)(a: any suitable answer than above)

1

1

114

1

11

14

11

114

20

11


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PAPER 3

1 ( a )

Score Rubric

3 [ Able to state all 11 readings correctly ]

2 decimal places

Unit cm3

Suggested answer

49.60, 40.10, 31.50, 24.10, 19.50, 15.10, 11.50, 9.60, 8.10, 8.10. 8.10

2 [ Able to state any 8 readings correctly ]

1 [ Able to state any 4 readings correctly ]

0 No response or wrong response

1 (b)

Score

Rubric

3[Able to design a table and record the time, buret reading and volume of gas liberated]

1. Time /minute2. Buret reading /cm3

3. Volume of gas liberated

Suggested answer:

Time

/min

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Buret

reading

/cm3

49.6

0

40.1

0

31.5

0

24.1

0

19.5

0

15.1

0

11.50 9.60 8.10 8.10 8.10

Volume

of gas /

cm3

0.00 9.50 18.1

0

25.5

0

30.1

0

34.5

0

38.1

0

40.0

0

41.5

0

41.5

0

41.50

2 [Able to design a table and record two of the 3 items (time, buret reading and volume of

gas liberated] // [Able to design table without unit]

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1[Able to give idea on table ]Suggest answer: 2 rows x 11 columns

1 (c)

Score Rubric

3 [ Able to draw 2 graphs of volume of carbon dioxide gas liberated against timefor both experiments on the same axes with all the 4 items below correctly ]

(i) suitable scale used

(ii) axes labelled correctly(iii) all points plotted correctly

(iv) smooth curve of graphs

2 [Able to draw the graphs of volume of carbon dioxide gas liberated against

time for both experiments on the same axes with at least 3 items correctly] //[Able to draw one of the graphs volume of carbon dioxide gas liberated against

time with at least 4 items abovebelow correctly]

1 [ Able to manipulate two items correctly ]


1 ( d )

Score Rubric

3 [Able to deduce the relationshipbetween the size of marble chips and the rate ofreaction correctly].

Suggested answer:Small pieces of marble chips have a large total surface area than that a large

pieces of marble chips of the same mass, course the time taken for reaction

more faster / rate of reaction more higher

2 [Able to give incomplete relationship]

Suggested answer:Small pieces of marble chips have a large total surface area time taken for

reaction more faster / rate of reaction more higher

1 [Able to give an idea ]

Suggested answer:Small pieces of marble chips have a large total surface area // time taken for

reaction more faster when size of reactant smaller // rate of reaction depend on

the size of reactant


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1 (e)

Score Rubric

3 [ Able to state three variables and the way to control them correctly ]

Example :

Manipulated variable :

Total suface area of marble Replace large marble chips with

small small marble chips

Responding variable :

Rate of reaction // time Measure the volume of gas collectedat half-minute interval

Fixed variable :

Mass of marble, volume ofhydrochloric acid, temperature

Use the same mass/5.0 g marble,same volume/50 cm3 and

concentration/ 0.1 mol dm-3

hydrochloric acid, same tepperaturein each of the experiment

2 [ Able to state any pair of variable and action correctly ]

1 [ Able to state any variable and any action correctly // any two variables

correctly // any two action correctly]


1 (f)

Score Rubric

3 [Able to state relationship small pieces of meat and time to cook correctly]

Suggested answer

Smaller pieces of meat has bigger total surface area

The larger surface area provides a larger area for absorbtion heat Increased obsorption of heat shorten cooking time// The rate of reaction

increases

2 [Able to give incomplete relationship ]

Suggested answer

[state the any two items above]

1 [Able to give an idea // state any one items above]

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2 (a)

Score Rubric

3 [Able to give the hypothesis accurately]

Suggested answer :The further the metal is from copper in the electrochemical series, the greater is

their potential different/ voltage reading. //

The further apart the metal is in the electrochemical series, the greater the

potential different/ voltage reading.

2 [Able to give the hypothesis almost accurately]

Suggested answer :The further the metal is from copper in the reactivities series, the greater is

their potential different/ voltage reading. //The further apart the metal is in the reactivities series, the greater the potential

different/ voltage reading.

1 [Able to state an idea of hypothesis]

Suggested answer :

The position of metal influence the different potential/ voltage reading.

Type of metal influence the different potential/ voltage reading.


2 (b)

Score Rubric

3 [Able to arrange all the 5 metals according to descending order ofelectropositivity correctly]

Suggested answer:Magnesium, Aluminium, Zinc, Iron, Copper

[a: formula]

2 [Able to arrange all the 4 metals but according to increasing order of

electropositivity correctly]

Example:

Mg, Al, Fe, Cu, Zn // Al, Zn, Fe, Cu, Mg // Al, Zn, Mg, Fe, Cu

1 [Able to arrange all the 5 metals but according to ascending order of

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electropositivity correctly]

Example ;Cu, Fe, Zn, Al, Mg


2 (c)

Score Rubric

3 [Able to state inference correctly].

Suggested answer

Electrical energy is not produced

No movement of electron because the same type of metal are used as

electrodes in a voltaic cell

2 [Able to state inference not completely].

Suggested answerElectrical energy is not produced // no movement of electron because the same

type of metal are used as electrodes in a voltaic cell

1 [Able to state an idea]

Example

No electric/electron/potential difference


2 (d)

Score Rubric

3 [Able to state three observations correctly]

Suggested answer:1 Zinc dissolved // becomes thinner

2 Copper becomes thicker // brown solid deposited

3 Blue solution becomes light blue /fading in colour

2 [Able to state two observation correctly]

1 [Able to state one observation/idea about observation of the cell]

0 No response given or wrong response

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2 (e)

Score Rubric

3 [Able to predict correctly]Answer: 1.0 V

2 [Able to predict almost correctly]

Example:

1.0

1 [Able to state an idea to arrange the metals]

Example:

Reading is higher than 0.5 / lower than 1.5


Essay

3 (a) - Statement of the problem

Score Rubric

3

[ Able to give the statement of problem correctly ]

Example :

How the effect on rusting when iron is in contact with another metals?

2

[ Able to give the statement of problem incorrectly ]

Example :

To investigate the effect of other metals on the rusting of iron

1 [ Able to state an idea the statement of problem]

Example :

To study the rusting of iron

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0 [ No response or wrong response]

3 (b) - variables

Score Rubric

3

[ Able to state All variables correctly ]

Suggested answer :Manipulated variable : Different types of metals// Different metals

Responding variable : Rate of rusting // Rusting of iron

Constant variable : Iron nails/temperature

2 [ Able to state any two variables correctly ]

1 [ Able to state any one variables correctly ]

0 [ No response or wrong response]

3 (c) - hypothesis

Score Rubric

3 [Able to give the hypothesis accurately]

Suggested answer :When a more electropositive metal is in contact with iron, the metal inhabits

rusting // When a less electropositive metal is in contact with iron, the metal

speed up rusting // Iron rusts faster when in contact with metal less

electropositive

2 [Able to give the hypothesis almost accurately]

Suggested answer :

When a more reactive metal is in contact with iron, the metal inhabits rusting

1 [Able to state an idea of hypothesis]

Suggested answer :

When a less electropositive metal is in contact with iron, the metal inhabits

rusting


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3 (d) - Apparatus and materials

Score Rubric

3

[ Able to give the list of the apparatus and substances correctly and

completely]

Suggested answer :

Apparatus : Five test tubes, test tube rack

Materials : sand paper, five iron nails, magnesium strip, zinc strip, tin strip,copper strip, hot agar-agar/jelly solution mixed with potassium

hexacyanoferrate(III) solution and phenolphthalein indicator

2

[ Able to give the list of the apparatus and substances correctly and but notcompletely]

Example :

List of apparatus and materials

Test tube, iron nail, magnesium,zinc, tin,copper,water, potassiumhexacyanoferrate(III) / phenolphthalein indicator

1

[ Able to give an idea about the list of the apparatus and materials correctly]

Example :

Any one apparatus and two materials

0 [No response or wrong response]

3 (e) - Procedure of the experiment

Score Rubric

3

[ Able to state allprocedures correctly ]

Suggested answer :

1. Clean all the metal strips with sand paper

2. Coil the metal strip around the iron nails and then put in the each test tube3. Pour the same volume of hot agar-agar/jelly solution has been mixed with

potassium hexacyanoferrate(III) and phenolphthalein indicator

4. Leave the test tubes aside for one day

5. Compare the intensity of the blue and pink colour in each test tube andrecorded

2 [ Able to state 3 steps of procedures correctly ]

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Example : Steps 2,3,5

1[ Able to state 2 steps of procedures correctly ]

Steps 2,3

0 [No response or wrong response]

3 (f) - Tabulation of data

Score Rubric

3

[ Able to exhibit the tabulation of data correctly ]

Tabulation of data has 6 columns and 3 rows

Example :

Test tube A B C D E

Intensity of

blue colour

Intensity ofpink colour

2

[ Able to exhibit the tabulation of data less accurately ]


Example :

Test tube A B C D E

Observation

1

[ Able to state an idea about the tabulation of data ]


0[No response or wrong response]

Total 3 6 = 18Max 17

Nota utk pemeriksa*

Markah Kertas 1 + Markah Kertas 2 + Markah Kertas 3 = Markah keseluruhan

2

50 + 100 + 50 = 100%

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2

END OF MARKING SCHEME

SPM Percubaan 2007 SBP Chemistry Marking Scheme

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