Chem JUJ K1 K2 K3 Skema Jawapan SET 2

(1)

4541 Set 2 © Hak Cipta JUJ Pahang 2017 1

SKEMA JAWAPAN KERTAS 1

JUJ KIMIA SET 2 - 2017

1 D 11 C 21 A 31 D 41 C

2 C 12 B 22 D 32 C 42 A

3 C 13 B 23 C 33 A 43 B

4 C 14 B 24 D 34 A 44 B

5 A 15 C 25 A 35 A 45 A

6 B 16 C 26 C 36 B 46 D

7 B 17 C 27 C 37 A 47 A

8 C 18 A 28 B 38 D 48 B

9 C 19 D 29 D 39 B 49 B

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MARKING SCHEME PAPER 2 SET 2 JUJ CHEMISTRY 2017

Question No Mark Scheme Sub 2. one different Sample answer :

1. Same number of proton /proton number // same number of electron

2. Different number of neutron / nucleon number

1 1

2

(b) (i) 70 / 70oC 1 1

(ii) 1. Heat energy absorbed

2. is used to overcome the forces of attraction between particles

1 1

2

(iii) Correct arrangement (at least 3x3 with same size & do not

overlapping each other) 1 1

Total marks 9

Question No Mark Scheme Sub

Mark

2 (a) (i) The chemical formula that shows the simplest ratio of atoms of each element in the compound

1 1

(ii) C2H4O 1 1

(b) 1. value of n

2. Molecular formula Sample answer :

(CH2) n = 42 // (12+ 2(1))n = 42 // 14n = 42 // n = 3

(3)

(iii) Argon atom has achieved stable octet electron arrangement 1 1

(b) (i) Cl 1 1

(ii) The forces of attraction between nucleus and electron in Cl

atoms is stronger than Na atom.

1 1

(c) (i) Ionic bond 1 1

(ii)

1.Correct number of ion and nucleus is labelled 2.Correct electron arrangement and charged

1

1 2

(iii) 1. Soluble in water//

2. High melting and boiling point//

3. Conduct electricity in aqueous and molten state

 Any two

(iii) Flavouring agent//thickening agent//colouring agent 1 1

(iv) Analgesic // paracetamol 1 1

(b) (i) N2+3H2  2NH3

1. Correct formula of reactants and products 2. Balanced equation

(4)

Mark Mark

5 (a) (i) Increase of hydrogen gas per unit time // decrease of mass of zinc per unit time

1 1

(b) (i) 1. draw the triangle 2. calculation

43.5-29 cm3 // 14.5 cm3 // 0.242 cm3 s-1

(iii) Because the concentration of acid decrease with time 1 1 (c) (i) Volume of gas / cm3

2. remain the volume and concentration of hydrochloric acid. 1 1

2

(d) (i) Put 5 g/a packet of fine sugar in hot water and cold water in two cups. Sugar in hot water dissolve faster.

1 1

(ii) 1. temperature higher in hot water

2. water particles has higher kinetic energy

1 2. The wooden splinter lights up

1 1

2

(iv) 1. Suggest the suitable electrode (can infer from diagram) 2. functional diagram

3. correct label :

Anode : silver electrode ; Cathode : iron spoon Electrolyte : silver nitrate solution

(5)

(iii) 1. Change copper electrode to silver electrode // change zinc electrode to magnesium electrode// any suitaible pair of electrodes

2. Reason :

Distance between Ag and Zinc / Mg and Cu in electrochemical series is further

1 (ii) 1. Reaction I = esterification

Functional

Alkene But-1-ene

Y

// Carboxyl group

Carboxylic acid Butanoic acid

(6)

Mark Mark

(b) 1. Correct formula of reactants and product 2. balanced

5. % of carbon atom by mass in propene is higher than propane.

6. Propene produces more soot than propane

1

2. W= copper(II) sulphate 3. X = nitric acid 6. Double decomposition reaction // precipitation reaction 1

Correct formula of reactants

7 & 8. Reaction I : Na2CO3 + CuSO4  CuCO3 + Na2SO4 9& 10. Reaction II : CuCO3 + HNO3 Cu(NO3)2 + CO2 +H2O

2+2

(b) Compare and contrast :

Similarities :

1. Both experiment produce black residue 2. Both experiment released gas when heated Differences:

3. Exp I produced colourless gas and Exp II produced brown gas 4. Exp 1 turns the limewater chalky and Exp II turns moist blue litmus paper to red

* Choose any 3

1+1+1

6 4. mole

5. ratio mole

(7)

Question No Mark scheme Sub

mark

(c) 1.Egg shells contain calcium carbonate 2. Calcium carbonate can react with acid 3. Calcium carbonate can dissolved in acid

4. Egg shell becomes soft//easier to insert in the bottle

1

Exothermic Endothermic

Energy profile diagram

-Correct level and label energy

-correct equation & H

-Correct level and label energy

-correct equation & H Total

energy content

Total energy content of the reactants is higher than products

Total energy content of the products is higher than reactants

1+1

3. precipitate D (can infer from procedure) 4-9. procedure

10. data

11-12. calculation

Sample answer :

1. Solution A = sodium chloride solution 2. solution B silver nitrate solution, 3. Precipitate D = silver chloride

Procedure :

4. Measure [20 – 100 cm3] of sodium chloride [any suitable solution] [0.5 – 2.0 moldm-3] solution and pour the solution into a plastic/polystryrene cup

5.Measure [20 – 100 cm3] of silver nitrate [any suitable solution] [0.5 – 2.0 moldm-3] solution and pour the solution into another plastic/polystryrene cup

6. record initial temperature for both solutions

(8)

7. pour sodium chloride solution quickly into the silver nitrate solution

8.stir the mixture

9. record the highest temperature reached

10. Initial temperature of sodium chloride solution = T1oC Initial temperature of silver nitrate solution = T2 oC

Average Initial temperature = (T1+ T2)/2 = Ta oC

2. oxidation 3. reduction

Half equation

4. Zn  Zn2+ + 2e 5. Cu2+ + 2e  Cu

6. Name the ion present in the colourless solution = copper(II) ions

1

Role 3. Reducing agent 4. Oxidizing agent

1+1

1+1 4

(b) Sample answer : 1. Metal : Zn/Al

Procedure :

2. Clean Zn/Al strip and iron nail with sand paper

3. Coil Zn/Al strip around the iron nail and put in a test tube 4. Put the iron nail only into another test tube.

5. Pour the hot agar-agar/jelly solution that has been mixed with potassium hexacyanoferrate(III) and phenolphthalein indicator until the iron nail immersed into both test tube.

1

(9)

Question Answer Sub

mark

marks

6. Leave the test tubes aside for a few days.

7. Observation

Pair of metal Observation

Zn/Al and iron nail pink spot form

Iron nail Blue spot form

Half equation for oxidation of metals 8. Test tube I : Zn  Zn2+ + 2e 9. Test Tube II : Fe  Fe2+ + 2e

10. Conclusion

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

iron does not rust when in contact with a more electropositive metal

1

1 1

1

10

Total marks 20

(10)

PERATURAN PEMARKAHAN KIMIA KERTAS 3 JUJ SET 2 2017

Question Rubric Score

1(a)

Able to state the colour change correctly

Answer:

Pink colour change to colourless

3

Able to state the colour change less correctly

Sample answer:

Purple to colourless

2

Able to state an idea of colour

Sample Answer:

Pink // Colourless// Purple

1

No response or wrong response 0

1(b)

Able to record all burette readings accurately to 2 decimal places

Answer:

Titration Initial reading (cm3) Final reading (cm3) I 0.00 26.00

II 0.50 24.50 III 5.50 30.50

3

Able to record all the burette readings correctly to 1 decimal places or able to record at least 4 reading correctly // uniform decimal places

2

Able to record at least 2 burette reading correctly without

decimal places 1

(11)

1(c)

Able to consruct a table that contains the following information.

1. Hading in the table : Set, Initil reading/cm3, Final reading/cm3, Volume of acid/cm3

2. Transfer all the burette readings from 1(b) correctly 3. With unit at the heading

Sample answer:

Titration Initil reading/cm3

Bacaan awal/cm3

Final reading/cm3

Bacaan akhir/cm3

Volume of acid/cm3

Isipadu asid/cm3

I 0.00 26.00 26.00

II 0.50 24.50 24.00

III 5.50 30.50 25.00

3

Able to construct a table less correctly

2 Able to construct a table that contains the following information

1. Headings in the table : suitable heading

2. 2 column with heading without data/ 2 column only

Sample answer:

Initial reading Final reading

1

(12)

1(d)

Able to calculate the average volume and concentration of hydrochloric acid with unit correctly

Answer:

Average volume of hydrochloric acid = 26.00 + 24.00 + 25.00

--- = 25.00 cm3 --- p1 3

Concentration of hydrochloric acid MHCl VHCl = 1

MNaOH VNaOH 1

MHCl X 25.00 = 1

1.0 X 50.00 1 ---- p2

// 25.00 MHCl = 50.00

MHCl = 50.00 25.00

= 2.0 mol dm-3 ---- p3

3

Able to calculate the average volume and concentration of

hydrochloric acid correctly without unit 2

Able to calculate volume of acid OR concentration of acid

correctly 1

1(e)

Able to classify all the acids into strong and weak acid correctly

Strong acids Asid kuat

Weak acids Asid lemah

Sulfuric acid Nitric acid

Citric acid Ethanoic acid

3

Able to classify at least 3 acids correctly 2

Able to classify at least 2 acids correctly/reverse 1

(13)

2(a)

Able to state all inferences correctly

Test tube A B C D

Inference Iron nail does not

Able to state 3 inferences correctly 2

Able to state 2 inferences correctly 1

2(b)

Able to state the relationship between manipulated varible and responding variable with direction correctly

Sample answer:

When a more/less electropositive metal / higher/lower than iron in Electrochemical series is in contact with iron, iron (nail) does

not rust/rust

3

Able to state the hypothesis less correctly Sample answer:

The rusting of iron is faster / slower, if a less / more

electropositive metal is in contact with iron/Fe 2

Able to give an idea of hypothesis Sample answer:

Iron rust when in contact with other metal // other metal affect the rusting of iron.

1

2(c)

Able to state all the variables correctly

Sample answer:

Manipulated variable : Type / different electropositive metal Responding variable : Rusting // presence of blue sport Constant variable : Type of iron nail // iron //medium in which the iron are kept

3

Able to state any two of variables in this experiment correctly 2 Able to state any two of variables in this experiment correctly 1

(14)

2(d)

Able to give one operational definition of the experiment correctly with the following aspects:

i) what you do ii) what you observe

Sample answer:

1. when iron nail is coiled/in contact with a less

electropositive metal (copper)/metal located below iron in electrochemical series

2. Rusting of iron is the formation of blue spot/colouration

3

Able to state at least two criteria correctly

Sample answer:

Rusting of iron is the formation of blue spot /colouration

or

when iron nail is coiled/in contact with a less electropositive metal

2

Able to state an idea of operational definition

Sample answer:

Blue spot/rusting occur 1

2(e)

Able to predict the observation correctly

Answer:

The intensity of blue spot/colouration is very high//higher than test tube B.

3

Able to predict the observation Sample answer:

The intensity of blue spot/colouration is high

2

Able to predict the observation Sample answer:

Blue spot/colour

1

(15)

2(f)

Able to state the relationship correctly between the time taken and the amount of rust form correctly

1. Time taken 2. Formation of rust 3. Comparison

Sample answer:

The longer the time taken, the bigger/greater/larger the rust form //the longger the time taken, more rust is form

//the rust form is greater/bigger/larger when the time taken is longer

//the rust form in one week is more/bigger/greater/larger than one day

3

Able to state the relationship between the time taken and the amount of rust form less correctly

1. Time taken/Formation of rust

Sample answer:

The rust form is bigger/greater/larger

//the form is directly proportional to the time taken

2

Able to state any idea of relationship Sample answer:

The rust is form/change//rust is small/less

1

(16)

3(a)

Able to give the problem statement correctly

Sample answer:

How does the effectiveness of cleansing action of two different types of cleansing agent in hard water?

// What is the difference in effectiveness of cleansing action in hard water using soap and detergent?

3

Able to give the problem statement less correctly

Sample answer:

How does different type of cleansing agent affect the effectiveness of cleansing action in hard water?

// To investigate the effectiveness of different type of cleansing agent in hard water.

2

Able to give an idea of statement of the problem

Sample answer:

To study the effectiveness of cleansing action in hard water

1

3(b)

Able to state all variables correctly

Sample answer:

Manipulated variable :Types of cleansing agent//soap and detergent

Responding variable : Effectiveness of cleansing agent//ability to remove the oily stains on cloth

Constant variable : Hard water//Cloth with oily stains//Size of cloth

3

Able to state any two variables correctly 2

Able to state any one variable correctly 1

(17)

3(c)

Able to state the relationship between the manipulated variable and the responding variable correctly

Sample answer:

Detergent is more effective than soap in hard water.

// Detergent in hard water can remove the oily stains on cloth while soap cannot.

3

Able to state the relationship between the manipulated variable and the responding variable incorrectly

Sample answer:

Detergent is more effective // Soap is less effective

// Detergent in hard water can remove the oily stains on cloth

//soap cannot remove stain on cloth.

2

Able to state an idea of hypothesis 1

3(d)

Able to give the completely list of the apparatus and materials Answer:

Apparatus:

Beakers, measuring cylinder, glass rod

Material:

Soap, detergent, [cleansing agent X dan cleansing agent Y], 0.5 - 1 mol dm-3 magnesium sulphate solution/[sea water/hard water], 2 pieces of cloth with oily stains.

3

Able to give the list of the apparatus and materials correctly but not completely

Answer: Apparatus:

Any containers, glass rod

Material:

Cleansing agent, cloth with oily stains.

2

Able to give two materials and at least one apparatus

Answer : Material:

Soap solution / detergent, hard water [any container]

1

No response or wrong response

(18)

3(e)

Able to state all procedures correctly

Sample answer :

1. Label 2 beakers as A and B respectively

2. Fill all the beakers with [50 - 100 cm3 ]of hard water / magnesium sulphate solution

3. Add cleansing agent X/detergent in beaker A and

cleansing agent Y/soap in bikar B.

4. Place a piece of cloth with oily stain into each beaker

5. Stir the solution in each beaker using glass rod until no

change can be observed

6. Wash the oily stain on each piece of cloth using the

solution in each beaker 7. Record the observation.

3

Able to state three steps of procedures correctly

Steps 2, 3, 5, 6,

2

Able to state two steps of procedures correctly

Steps 2, 3, 6

1

PERATURAN PEMARKAHAN TAMAT

3(f)

Able to exhibit the tabulation of data that includes the following information.

1. Headings

Sample answer :

Beaker Observation

A B

2

Able to tabulate the data incompletely

1. Titles without unit

Sample answer:

Beaker

1