Ulangkaji Akhir Menjelang Spm Answer

Ulangkaji Terakhir Menjelang SPM CHEMISTRY1

STRUCTURE OF ATOM

1 Table 1 shows the incomplete information about 3 atoms; X, Y and Z.

Atom Proton number Number of neutron Number of electron

X 8 6Y 6 6Z 17 17

Table 1

(a) State the name of subatomic particles that are found in nucleus of an atom.

Proton, neutron… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … .[1 mark]

(b) (i) What is the term of the total number of protons and neutrons in an atom?

Nucleon number… … … … … … … … … … … … … … … … … … … … … … … … … … ..[1 mark]

(ii) The total number of protons and neutrons for atom Z is 35.What is the number of neutron in atom Z?

35-17=18… … … … … … … … … … … … … … … … … … … … … … … … … … … … ..[1 mark]

(iii) Write the symbol for atom Z in the form of A X. Z

35 Z18 … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … …

[1 mark]

(iv) Draw the atomic structure of atom Z.

[1 mark]

Z

17 protons

18 neutrons

2.8.7


(c) Atom X and atom Y are isotopes of an element.

(i) What is the proton number of atom X?

6 … … … … … … … … … … … … … … … … … … … … … … … … … … …[1 mark]

(ii) Write the electron arrangement of atom Y.

2.4 … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … …[1 mark]

(iii) What is valence electron of atom X?

4 … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … …[1 mark]

(iv) Why atom X and atom Y has same chemical properties?

They have same valence electron.… … … … … … … … … … … … … … … … …[1 mark]

(v) State one use of the isotope X in archaeology field.

Estimate the age of the fossils… … … … … … … … … … … … … … …[1 mark]

2 Diagram 2 shows the chemical symbols which represent three elements X, Y and Z The letters used are not the actual symbols of the elements.

9 X 4

32 Y15

31 Z15

Diagram 2

(a) (i) What is meant by proton number?

Number of protons in the atom… … … … … … … … … … … … … … … … .. [1 mark]

(ii) State the proton number for atom X

4 … … … … … … … … … … … … … … … … … … … … … … … … … .. [1 mark]

(b) What is represented by the number 32 for the element Y?


Nucleon number … … … … … … … … … … … … … … … … … … … … … … … … … … … [1 mark]

(c) (i) Atom Y and Z are isotopes. State the difference between the two atoms.

Number of neutron // nucleon number … … … … … … … … … … … … … … …[1 mark]

(ii) State one use of isotopes in daily life.

Carbon –14 estimate the age of fossils… … … … … … … … … … … … … … … … … [1 mark]

(d) (i) Write the electron arrangement of atom Y.

2.8.5 … … … … … … … … … … … … … … … … … … … … … … … .. [1 mark]

(ii) Determine the number of valence electron for atom Y.

5 … … … … … … … … … … … … … … … … … … … … … … … … … … … .. [1 mark]

(ii) Draw the electron arrangement for atom Z.

2.8.5

[2 marks]


3 Diagram 3.1 shows the arrangement of particles of substance X at different temperatures.

(a) What is the physical state of substance X at

(i) 60 oC : solid......................................

(ii) 90 oC : liquid ......................................................... [2 marks]

(b) State the movement of particles of substance X at 60 oC.

Vibrate and rotate at fix position , cannot move freely [1 mark]

(c) Graph 3.2 shows the graph of temperature against time when substance X is heated from 60 oC to 90 oC.

(i) What is meant by melting point?Temperature at which solid change to liquid at certain pressure

… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … …[1 mark]

(ii) Based on Graph 3.2, state the melting point of substance X.78 oC… … … … … … … … … … … … … … … … … … … … …

[1 mark]

(iii) Explain why the temperature remains constant from t1 to t2.

Heat absorbed is used to overcome the force of attraction between particles

Diagram 3 90 oC60 oC

Temperature / oC

Time / sGraph 3.2

60

78

90

t0 t1 t2 t3


[2 marks]

(d) (i) Substance X cannot conduct electricity in any state.State the type of particles of substance X.

Molecules .................................................................................[1 mark]

(ii) Table 3.3 shows two substances.

Magnesium oxide

Carbon dioxide √

Which substance has the same type of particles as substance X?Tick (√ ) the correct answer.

[1 mark]

CHEMICAL FORMULAE & EQUATIONS

4 (a) Diagram 4 shows that a magnesium atom is two times heavier compare to a carbon atom. Relative atomic mass of carbon is 12.

Diagram 1

(i) Complete the following equation.

Relative atomic mass… … … .. = The average mass of one atom of an element 1/12 × the mass of an atom of carbon-12

[1 mark]

Table 3.3

Carbon atomsAtom karbon

Magnesium atomAtom magnesium


(ii) One atom of element X is two times heavier than one magnesium atom. What is the relative atomic mass of element X?

48 … … … … … … … … … … … … … … … … … … … ...................................................[1 mark]

(b) A student heats 20 g of calcium carbonate strongly. It decomposes according to the equation below.

CaCO3 → CaO + CO2

(i) State the name of the products.

Calcium oxide and carbon dioxide … … … … … … … … … … … … … … … … … ...[1 mark]

(ii) Describe the chemical equation in terms of quantitative aspect.

1 mol of calcium carbonate decomposes to form 1 mol of calcium oxide and 1 mol of carbon dioxide gas… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … ...

[1 mark]

(iii) Calculate the mass of calcium oxide produced.[ Relative atomic mass: C = 12 ; O = 16 ; Ca = 40]

Mol of CaCO3 = 20/100 = 0.2 molRatio:

CaCO3 CaOFrom equation 1 1From calculation 0.2 0.2Mass of CaO = mol x molar mass of CaO = 0.2 x 56 = 11.2 g

[3 marks](iv) Calculate the volume of carbon dioxide produced at room conditions.

[Molar volume of gas = 24 dm3 mol-1 at room conditions]

Mol of CaCO3 = 20/100 = 0.2 molRatio:

CaCO3 CO2

From equation 1 1From calculation 0.2 0.2Volume of CO2 = mol x molar volume = 0.2 x 24= 4.8 dm3 = 4800 cm3

[2 marks]


PERIODIC TABLE OF ELEMENTS & CHEMICAL BONDS

5 Diagram 5 shows the symbols of the atoms of element X, Y and Z.The letters used are not the actual symbols of the elements.

7 23 39

X Y Z 3 11 19

Diagram 5

(a) What is the valence electron of the atom of element X.

1 … … … … … … … … … … … … … … … … … … … … … … … … … ..........................[1 mark]

(b) (i) Identify the position of element Y in the Periodic Table of Elements.

Group 1, Period 3… … … … … … … … … … … … … … … … … ................[1 mark]

(ii) Explain why element Y is placed at the position identified in (b) (i).

It has 1 valence electron, 3 electron shell filled with electron … … … … … ................[1 mark]

(c) Element X, Y and Z can react with water.

(i) Which of the element most reactive in their reactions with water.

Z … … … … … … … … … … … … ................[1 mark]

(ii) Explain your answer in (c) (i).Z has largest atomic radius compare to Y and X.Attraction force between nucleus and valence electron becomes weaker.The valence electron is easier to be released to achieve stable octet electron arrangement.

[3 marks]

(iii) Write the chemical equation for the reaction between element that you choose in (c) (i) and water.

2Z + 2H2O 2ZOH + H2… … … … … … … … ...............[2 marks]


(d) Argon is placed at the same period with element Y in the Periodic Table of Elements.

(i) Compare the atomic size argon and element Y.[ Given that proton number of argon is 18 ]

Y has larger atomic size than Argon… … … … … … … … … … … … … ...............[1 mark]

(ii) Explain your answer in (d) (i).

Argon has more protons compared to Y.Attraction force between nucleus and valence electron become stronger.Valence electrons are pulled nearer to the nucleus, smaller atomic size.

[2 marks]

6 Diagram 6 shows part of the Periodic Table of Elements. Q, T, X, Y and Z do not represent the actual symbol of the elements.

3Q7

4T9

6X12

7Y14

8Z16

Diagram 6

Using the letters in the Periodic Table of the Elements in Diagram 3, answer the following questions.

(a) (i) Write the electron arrangement of atom Q.

2.1… … … … … … … ..… … … … … … ...............................[1 mark]

(ii) Write the formula of ion Q.

Q+… … … … … … … … … … … … … … … … … … … … … … ..… … … … … … ...............................


[1 mark]

(b) State one element which exists as a diatomic molecule.

Z … … … … … … … … ..… … … … … … ...............................[1 mark]

(c) (i) Arrange the elements Q, T, X, Y and Z according to the atomic size in descending order.

Q T X Y Z… … … … … … … … … … … ..… … … … … … ...............................[1 mark]

(ii) Explain your answer in (c) (i) based on nuclei attraction force on the valence electrons.

Across the period from left to right, the number of proton of element increases.Attraction force between nucleus and valence electron become stronger.Valence electrons are pulled nearer to the nucleus, smaller atomic size.

[ 2 marks](d) X reacts with Z to form a compound.

(i) What is the type of the compound formed?

Covalent compound … … … … … … … … … … … … … … … … … … … … … … … … … … …[1 mark]

(ii) State one physical property of the compound formed.low melting and boiling point. ORcannot conduct electricity in any state. ORsoluble in organic solvent, insoluble in water. [ANY one] [1 mark]

(iii) Draw the electron arrangement for the compound formed.

Draw XZ2 [CO2]

[2 marks]


7 (a) Element X reacted with oxygen to form a compound which cannot conduct electricity at any state. Suggest one example of element X. Write chemical equation between element X and oxygen.Element X: Carbon dioxide

X + O2 CO2 [3 marks]

(b) Table 7 shows the proton number of elements P, Q and R.

Element Proton number

P 6 (2.4)

Q 11(2.8.1)

R 17(2.8.7)

Explain the formation of a compound that has high melting point. [6 marks]1. Electron arrangement of Q atom is 2.8.12. A Q atom loss one electron to achieve stable electron arrangement to form Q+ ion.3. Electron arrangement of R atom is 2.8.74. A R atom receive 1 electron from Q atom to achieve stable octet electron arrangement to form R- ion.5. The Q+ ion and R- ion are attracted by strong electrostatic force ionic compound, QR.6. Diagram

(c)

Identify U and solvent V. Explain the differences between two solutions.1. U is an ionic compound, for example, glacial hydrogen chloride, that soluble in water to form free moving Hydrogen and

chloride ions that can conduct electricity in molten/aqueous state and change the blue litmus paper to red.

2. U is insoluble in organic solvent V, for example, propanone. So the ions are still in the fix position and cannot move

freely. Thus, it cannot conduct electricity and no change the litmus paper.

(d)

(i) State the type of compound, type of bond and type of particles of two substances Sodium chloride Carbon dioxide

Type of compound Ionic compound Covalent compoundBond Ionic bond Covalent bondParticles Ions molecules

(ii) Explain the formation of carbon dioxide and draw the electron arrangement.1. Atom Carbon has four valence electrons, with an electron arrangement of 2.42. It needs four more electrons to achieve the stable octet electron arrangement3. One atom of C contributes 4 electrons for sharing4. Atom O has six valence electrons, with an electron arrangement of 2.65. It needs two more electron to achieve the stable octet electron arrangement6. One atom of C share two pairs of electrons with two atoms of O7. Covalent compound of CO2 is formed.8. Diagram

Carbon dioxideSodium chloride

U

Solution ZCan not conduct electricityNo change with litmus paper

Solution YCan conduct electricityChange litmus paper

+ water + Solvent V


7. Table 7.1 shows the electron arrangement of elements U, V and W.

Element Electron arrangement

U 2.6

V 2.1

W 2.8.1

a) Based on the Table 7.1, b)

i) Identify one metal and one non-metal element. Metal: W OR V; non metal: U[2 marks]

ii) State the group and period of element W in the Periodic Table of Elements.Group 1, Period 3 [2 marks]

(iii) The reaction between element U and W produces a compound. State one property for the compound formed.high melting and boiling point. ORcan conduct electricity in molten/aquesous state. ORsoluble in water, insoluble in organic solvent. [ANY one]

Draw the electron arrangement for the compound formed.Draw ionic compound, W2U

[3 marks]

b) Table 7.2 shows the observations of element V and element W when react with water.

ElementUnsur

ObservationPemerhatian

V

Element V Unsur V

water air

Element V, moves slowly at random on the water surface with a little fizzing sound.The solution formed turns red litmus paper to blue.

Table 7.1


W

Element W Unsur W water air

Element W, moves rapidly at random on the surface of the water with a ‘hissing’ sound.The solution formed turns red litmus paper to blue.

(i) Write the chemical equation when element V reacts with water.2V + 2 H2O 2 VOH + H2 [3 marks]

(ii) Compare the reactivity of elements V and W when react with water. Explain your answer.

1. W has higher reactivity compared to V when react with water.2. W has larger atomic radius compare to V.3. Attraction force between nucleus and valence electron becomes weaker.4. The valence electron is easier to be released to achieve stable octet electron arrangement.

[4 marks](c) Diagram 7 show the set up apparatus used to compare the electrical conductivity of solutions P and Q.

Based on the observations in Diagram 7,

(i) Identify the type of compound of solution P and solution Q.P: ionic compound; Q: covalent compound [2 marks]

(ii) Explain why there is a difference in the observations.In molten/aqueous states, the ions in solution P can move freely to carry electrical charges => bulb lights up.Solution Q are Covalent compounds exist as molecules; there are no free moving ions, so they cannot conduct electricity in any state. [4 marks]

Table 7.2

Solution Q Larutan Q

Carbon electrodeElektrod karbon

Solution PLarutan P

Bulb lights upMentol menyala

Bulb does not light upMentol tak menyala

Diagram 7


ELECTROCHEMISTRY

8 (a) Table 8.1 show the set up of apparatus of two experiments to investigate electrolysis process by using different electrodes.

Experiment Apparatus set-up

I

II

Compare and contrast Experiment I and Experiment II. Include in your answer, the observations at the anode and cathode, the name of the products formed at the anode and cathode and half equations for the reactions at the electrodes in both cells.

[10 marks]

(b) A student intends to electroplate an iron spoon with copper to prevent it from rusting.Design a laboratory experiment to electroplate the iron spoon.Your answer should consist of the following

Procedures of the experiment. A labelled diagram showing the set up of apparatus. Half equations for the reactions at both electrodes. Observation at both electrodes

[8 marks]

Table / Jadual 8.1

Copper electrodes

Copper(II) sulphate solution

A


Carbon electrodes

Elektrod karbon

A


a) Experiment I Experiment II

Observation 1 Anode: copper electrode dissolve// becomes thinner

3a) Cathode: Brown solid is deposited // Copper electrode becomes thicker.

2) Anode: colourless bubbles gas are released.

3b) Cathode: Brown solid is deposited // Copper electrode becomes thicker.

Products at 4. Anode:copper (II) ions

6a)Cathode: copper metal

5. Anode: oxygen gas

6b)Cathode: copper metal

Half Equation 7.Anode: Cu Cu2+ + 2e-

9a)Cathode: Cu2+ + 2e-Cu

8. Anode: 4OH- O2 + 2 H2O + 4e-

9b) Cathode: Cu2+ + 2e-Cu

b) Chemicals:

1.A: Battery, 250 cm3 beaker, connecting wires with crocodile clips, ammeter, switch, rheostat.

M: 1 mol dm-3 silver nitrate, AgNO3 solution, silver plate, iron spoon, sandpaper.

Procedure:

2. Iron ring is then connected to the negative plate on the battery 3. silver plate is connected to the positive terminal of the battery//Iron ring is made as cathode while silver plate is made as anode

4. Both plates are immersed into the silver nitrate solution.

5. The circuit is completed.

Diagram:

Half equation:

8. Cathode: Ag+ + e Ag 9. Anode : Ag Ag+ +e

Observation:

10. Cathode: Grey /silvery solid is deposited 11. Anode: silver become thinner//dissolved

Dilute Silver nitrate solution

6. Functional apparatus7. Label (silver plate ,

Silver nitrate solution ,Iron spoon)

Silver plate


7 Diagram 7.1 shows the set-up of apparatus to investigate the electrolysis of magnesium chloride 1.0 mol dm-3 solution.

Diagram 7.1

(a) (i) Based on Diagram 7.1, state the name of the products at the cathode and the anode. Explain your answer in term of factor that affects discharge of ion.

[8 marks]

(ii) Predict the product at anode and cathode if magnesium chloride 1.0 mol dm-3 solution is replace by magnesium chloride 0.0001 mol dm-3 solution.

[2 marks]

(b) Diagram 7.2 shows the set up of apparatus when cell X is combined with cell Y.

Compare cell X and cell Y base on ; the name of the cells, energy conversion, the observations and half equations for the reactions at the electrodes in both cells.

. [10 marks]

Copper plate


Magnesiumplate

P Q R S

Cell X Cell Y

Copper plate

Diagram 7.2

V

Magnesium chloride 1.0 mol dm-3

AA

Carbon electrodes


2. a)i) Cathode (-ve) Anode (+ve)

Ions Attracted to 1. Mg2+, H+ 2. OH-, Cl-

Ions selectively disharged 3. H+ 4. Cl-

Products 5. Hydrogen gas 6. Chlorine gas

Factor 7. Hydrogen ion is located lower position in the ECS,

easily discharged

8. The concentration of chloride ions is higer, selectively discharged.

Half Equation 2 H+ + 2e-H2 2 Cl- + 2e-Cl2

Observation Colourless bubbles gas produced

Greenish yellow bubble gas produced

2

2

2

2

ii) Anode: Oxygen gas; Cathode: hydrogen gas

b) Cell X Cell Y

Name of the cell 1. Electrolytic cell 2. Chemical / Voltaic cell

Energy conversion 3. Electrical chemical 4. Chemical electrical

Observation 5. Anode(P): copper plate dissolves // thinner

6. Cathode(Q): brown solid deposited

7. Anode (S): magnesium plate dissolved

8. Cathode (R): brown solid deposited

Half equation 9.Anode: Cu Cu2+ + 2e-

10)Cathode: Cu2+ + 2e-Cu

11. Anode: Mg Mg2+ + 2e-

12. Cathode: Cu2+ + 2e-Cu

2

2

2

2

2

2

Max

10


ACIDS AND BASES

5 (a) Diagram 1 shows the observation in test tube I and test tube II when hydrogen chloride in tetrachloromethane and hydrogen chloride in water are reacted with zinc powder.

Test tube I II

Apparatus set-upSusunan radas

Hydogen chloride in tetrachloromethane+ zinc powder

Hydogen chloride in water + zinc powder

Observation No change. Bubbles of gas are produced.

Diagram 1

(i) State the ion that causes an acid shows its acidic properties.

Hydrogen ion… … … … … … … … … … … … … … … … … … … … ...........[1 mark]

(ii) Explain why the differences in observation in test tube I and II.

Water enables hydrogen chloride to ionize to form hydrogen ions to react with zinc powder to produce hydrogen gas. In tetrachloromethane, hydrogen chloride still exist as molecules, no reaction with zinc.

[2 marks]

(iii) State the name of the gas produced in test tube II

Hydrogen gas.… … … … … … … … … … … … … … … … … … … ...........[1 mark]

(iv) Write the chemical equation for the reaction between zinc and hydrochloric acid.

2 HCl + Zn ZnCl2 + H2 … … … … … … … ...........[2 marks]


(b) Table 2 shows the information of the solution A, solution B and solution C. Solution of A, B and C might be an acid and an alkali.

SolutionLarutan

InformationMaklumat

AIonises completely.The solution remain colourless when phenolphthalein is added.

BIonises partially.The solution remain colorless when phenolphthalein is added.

CIonises completely.The solution turn to pink when phenolphthalein is added.

Table 2

(i) Which solution has the lowest pH?

Solution A … … … … … … … … … … … … … … … … … … …[1 mark]

(ii) Give a reason for your answer in (b) (i).

It is strong acid that ionises completely.… … … … … … … … … … … … … … … …[1 mark]

(iii) Vinegar consists of an ethanoic acid. Describe a chemical test to verify the acid without using an indicator.

Add a little zinc powder into the test tube contains the vinegar. Colourless bubbles gas released that give a pop sound when a lighted wooden splinter is near to the mouth of the test tube.

[2 marks]

4 Hydrochloric acid, HCl is a strong acid. Table 4.1 shows two solutions of hydrochloric acid, HCl with different concentration.

SolutionConcentration /

mol dm-3 pH

A 1.0 1.0

B 0.001 3.0

Table 4.1


(a) what is meant by acid ?

Substance that ionizes in water to produce hydrogen ions and give the pH value below 7.0.[1 mark]

(b) pH value of the solution A and B are different. Explain why.

In solution A, the concentration is higher compared to solution B. The higher the concentration, the number of hydrogen ions per unit volume is higher, thus pH value is lower.

[3 marks](c) Diagram 4.2 shows the set-up of apparatus for titration of 25 cm3 of 1.0 mol dm-3 sodium hydroxide

solution with 1.0 mol dm-3 sulphuric acid, using phenolphthalein as indicator.

(i) State the colour change of the solution in the conical flask at the end point.

Pink to colourless.… … … … … … … … … … … … … … … … … ... [1 mark](ii) State the type of the reaction occurred.

Neutralization.… … … … … … … … … … … … … … … … … … ... [1 mark]

(iii) Write the chemical equation for the reaction.

H2SO4 + 2 NaOH Na2SO4 + 2 H2O… … … … … … … … … ... [1 mark]

(iv) Calculate the volume of sulphuric acid needed to neutralise the sodium hydroxide solution.

b

a

bb

aa

VM

VM

Ma = 1.0, Va = ?, Mb = 1.0, Vb = 25, a =1, b = 2

Mb = 12.5 cm-3

[3 marks]

Solution A

25 cm3 of 1.0 mol dm-3

sodium hydroxide solution

Diagram 4.2


SALT

7 (a) A student has carried out an experiment to construct an ionic equation for the formation of lead(II) iodide.

Seven test tubes of the same size were labelled 1 to 7. A fixed volume of 5.0 cm3 of 1.0 mol dm-3

potassium iodide solution was placed in each test tube.

0.5 cm3 of 1.0 mol dm-3 lead(II) nitrate solution was added into test tube 1, 1.0 cm3 into test tube 2 and so on until 3.5 cm3 was added into test tube 7.

The heights of the precipitate formed in each test tube were measured.

The results are shown in Table 7.1

Test tube 1 2 3 4 5 6 7

Volume of 1.0 moldm-3

lead(II) nitrate solution/ cm3

0.5 1.0 1.5 2.0 2.5 3.0 3.5

Height of precipitate /cm 1.1 2.2 3.4 4.4 5.5 5.5 5.5

Table 7.1

(i) Based on Table 7.1, plot a graph of the height of the precipitate against volume of lead(II) nitrate solution on the graph paper provided.

[3 marks]

(ii) Determine the volume of lead(II)nitrate solution that had reacted completely with 5.0 cm3 of 1.0 mol dm-3 potassium iodide. 2.5 cm3

[1 mark]

(iii) Using the volume obtained in (a) (ii), calculate the number of moles of lead(II) ions and iodide ions that are required for the formation of lead(II) iodide.

Number of mol of lead (II) ions = mol0025.01000

)5.2(0.1

1000

MV

Number of mol of iodide ions = mol005.01000

)5(0.1

1000

MV

Then, calculate the number of moles of iodide ions that has reacted with 1 mol of lead(II) ions.0.0025 mol of lead(II) ions reacts with 0.005 mol of iodide ions,1.0 mol of lead (II) ions reacts with 2.0 mol of iodide ions. [4 marks]

(iv) Write the ionic equation for the formation of lead(II) iodide.Pb2+ + 2 I- PbI2 [2 marks]


(b) Diagram 7.2 shows a series of reactions for compound A. Compound A is insoluble in water.

(i) State the name of substances A , B , C and D. [4 marks]

A: Copper (II) carbonate; B: carbon dioxide; C: copper (II) oxide; D: copper (II) sulphate

(ii) State the ion presence in solution D that give the blue colour.Describe a chemical test to verify the ion. [3 marks]Copper (II) ions.Add NaOH until excess into the solution, a blue precipitate is formed, Cu2+ is present// Add a little NH3 into the solution, a blue precipitate is formed. Excess NH3, the blue precipitate dissolved to form dark blue solution, Cu2+ is present.

(iii) Why does gas B turns lime water milky?Write the chemical equation for the reaction occurred. [3 marks]

Carbon dioxide gas reacts with calcium hydroxide (limawater) to form calcium carbonate and water.CO2 + Ca(OH)2 CaCO3 + H2O

Compound A

(Green powder)

Colourless gas B

turns lime waterBlack powder C

Blue solution D

+

+Colourless gas B

turns lime water

Diagram 7.2

Heat

+ sulphuric acid


9 Diagram 9 shows a series of reaction starting from lead(II) carbonate, PbCO3.

PbCO3 + HNO3 + + H2O

Heat Crystallisation panaskan Penghabluran

PbO +

Diagram / Rajah 9

(a) Based on Diagram 9 :

Identify gas Y. Describe a chemical test to verify gas Y.Y: carbon dioxide gas. Bubbles the gas Y into the limewater. The limewater turs milky.

Describe a chemical test to determine the presence of anion in the solution X.

Compare and contrast the observation when solid X and lead(II) carbonate, PbCO3 are heated.2 Pb(NO3)2 2 PbO +4 NO2 + O2

Brown solid when hot, yellow solid when cold is formed, Brown gas which turns moist blue litmus red released. Another gas released relighted glowing splinter.PbCO3 PbO + CO2

Brown solid when hot, yellow solid when cold is formed. A gas turns the limewater milky released.

MANUFACTURED SUBSTANCES

1 (a) Diagram 1.1 shows ammonium sulphate formed from the reaction between substance X and substance Y. Substance X is produced from Contact process whereas substance Y from Haber process.

- Anions: Nitrate ion. - Add 2 cm3 of dilute sulphuric acid and 2 cm3 of iron (II) sulphate solution into the solution- Concentrated sulphuric acid is added slowly along the wall of the test tube- Brown ring is formed shows the presence of nitrate ion.

Solution X

Larutan X

Gas Y

Gas Y Solid X

Pepejal X

Contact processProses Sentuh

Haber processProses Haber

X

Y

Ammonium sulphateAmmonium sulfat


Diagram / Rajah 1.1(i) State the name of substance X and substance Y.

X : sulphuric acid… … … … … … … … … … … … … … … …

Y : ammonia… … … … … … … … … … … … … … … … … … … … … …[2 marks]

(ii) State one use of ammonium sulphate in agriculture field.

As fertilisers… … … … … … … … … … … … … … … …[1 mark]

(iii) Write the chemical equation for the reaction between substance X and substance Y.

H2SO4 + 2 NH3 (NH4)2SO4 … … … … … … … … … … …[2 marks]

(b) Diagram 1.2 shows the structure formula of a polymer.

H Cl

C C

H H n

Diagram /Rajah 1.2

(i) State the name of the polymer.

Polyvinyl chloride (PVC)… … … … … … … … … … … … … … … …[1 mark]

(ii) Draw the structure formula of it monomer.

H Cl

C C

H H

[1 mark]


(iii) Disposal of the polymer by burning is not suitable. Give a reason.

Cause air pollution … … … … … … … … … … …[1 mark]

(iv) The polymer is not suitable to be buried for disposing. Give a reason.

It’s non-biodegradable … … … … … … … … … … … … … …[1 mark]

(v) Suggest how to solve the problems in (b) (iii) and (b) (iv).

Recycle. … … … … … … … … … … … … …[1 mark]

(b) There are four types of glasses that are used in our daily lives.

(i) Name the major component of glass.Silica // silicon dioxide .........… … … … … … … … … … … … … … … … … … … .....

[1 mark]

(ii) Table 2 shows three types of glasses and their uses. Complete the table.

Type of glass/ Jenis kaca

Uses / Kegunaan

Borosilicate glassKaca borosilikat

Cookware / Alatan memasak Laboratory glassware / Alatan kaca makmal

Lead glass Decorative lamp /Lampu hiasan Prism / Prisma

Soda-lime glass Bottle / Botol Mirrors / Cermin

[2 marks]

(iii) Why is borosilicate glass suitable to make cookware and laboratory glassware? Withstand high temperature … … … … … … … … … … … …

[1 mark]

Table 2


1 Diagram 1 shows railway tracks and the arrangement of atom in alloy that made the railway tracks.

Diagram / Rajah 1

(a) State the name of alloy X.

Steel … … … … … … … … … … … … … … … … … … … … .....[1 mark]

(b) State the name of atom M.

Carbon … … … … … … … … … … … … … … … … … … … … … … … … … … … … … .....[1 mark]

(c) (i) Draw the arrangement of atom in pure iron.

[1 mark](d) Explain the difference of hardness of alloy Y and pure iron

1. In pure iron, the layer of atoms are arranged in orderly manner//same size

2. easily slides over each other when external force is applied on them.

3. The different size of foreign atoms in alloy are disrupt the orderly arrangement of atoms // prevent the layers of atom from slide each other when external force is applied.

Alloy X / Aloi XAtom iron /Atom ferum

Atom M


RATE OF REACTION

2 Diagram 2 shows the set-up of apparatus to study the rate of reaction between hydrochloric acid with sodium tiosulphate solution.

In this reaction, a 250 cm3 conical flask contained 50 cm3 of 0.2 mol dm-3 sodium thiosulphate solution, Na2S2O3 is placed on a white paper marked with the ‘X’ sign.

5.0 cm3 of 2.0 mol dm-3 hydrochloric acid was added to the sodium thiosulphate solution and the mixture swirled. At the same time the stopwatch was started. The time is taken as soon as the ‘X’ sign is no longer visible.

(a) In this reaction, a precipitate is formed. What is the colour of the precipitate?

Pale yellow… … … … … … … … … … … … … … … … … … … … … … … … ..[1 mark]

(b) Calculate the number of moles of HCl and the number of moles of Na2S2O3 used in the experiment.

Number of mol of HCl = mol01.01000

)5(0.2

1000

MV

Number of moles of Na2S2O3 = mol01.01000

)50(2.0

1000

MV

[2 marks]

Observer eye

‘X’ signWhite paper

Sodium thiosulphate solution

+ hydrochloric acid

250 cm3 conical flask

Diagram 2


(c) The chemical equation for the reaction occurred in this reaction is :

Na2S2O3 + 2HCl → 2NaCl + S + SO2 + H2OBased on the calculation in (b) and the chemical equation above, calculate the mass of the precipitate formed.[Given that the relative atomic mass of S = 32]Ratio:

HCl SFrom equation 2 1From calculation 0.01 0.005

Mass of S = mol x molar mass = 0.005 x 32= 0.16 g[2 marks]

(d) (i) State two factors that affect the rate of reaction in this experiment.

Temperature of sodium thiosulphate solution, concentration of acid / sodium thiosulphate[2 marks]

(ii) By using any one of the factor that you are stated in (d) (i), explain how the factor that you are stated in (d) (i) affect the rate of reaction.

1. Higher temperature will increase the kinetic energy of thiosulphate ions.2. Frequency of collisions between the H+ ion and thiosulphate ions increases.3. More collisions can overcome the activation energy.4. More effective collisions can be produce by thisulphate ion and hydrogen ion.5. Higher rate of reaction when temperature is higher. [4 marks]

9 (a) Table 9 shows the data from Experiment I, Experiment II and Experiment III that were carried out to investigate the factors that affects the rate of reaction.

Experiment ReactantsTemperature

/0C

Time taken for all the magnesium to dissolve

/s

I Excess hydrochloric acid+ 0.2g magnesium ribbon

30 50

II Excess hydrochloric acid+ 0.2g magnesium ribbon

40 20

III

Excess hydrochloric acid+ 0.2g magnesium ribbon+ copper(II) sulphate solution

40 15


Table 9

(i) Write the chemical equation for the reaction between magnesium and hydrochloric acid. Calculate the maximum volume of hydrogen gas produced.[ Relative atomic mass : Mg =24 ; molar gas volume : 24 dm3 mol-1 at room condition ]Mg + 2 HCl MgCl2 + H2

Number of mol of Mg = mol0083.024

2.0

massmolar

mass

Ratio: Mg H2

From equation 1 1From calculation 0.0083 0.0083

Volume of gas = mol x molar volume = 0.0083 x 24= 0.2 dm3 = 200 cm3

[5 marks]

(ii) Compare the rate of reaction between Experiment I and Experiment II or

With reference to collision theory , explain why there is difference in the rate of reaction.Experiment I and Experiment II

1. Exp II has a higher ROR than Exp I.2. Higher temperature will increase the kinetic energy of hydrogen ions and magnesium atom.3. Frequency of collisions between the H+ ion and magnesium atom increases.4. More collisions can overcome the activation energy.5. More effective collisions can be produce by Magnesium and hydrogen ion.6. Higher rate of reaction when temperature is higher.

Experiment II and Experiment III.1. Exp III has a higher ROR than II2. Catalyst provides an alternative pathway, which required lower activation energy.3. Catalyst lowers the activation energy of a reaction.4. More collisions between H+ ion and magnesium atom can overcome the lower activation energy. 5. Frequency of effective collisions increase.6. Hence, a higher rate of reaction with the presence of catalyst.

[5 marks]

(b) By using either the factor of size of reactant or concentration, describe an experiment how this factor affecting the rate of reaction.

[10 marks]


CARBON COMPOUND

1 Diagram 1 shows the structural formula of two of hydrocarbons.

H H H H

C C H C C H

H H H H

Ethene compound YDiagram 1

(a) State the name of the homologous series in which compound Y is placed.

Alkane … … … … … … … … … … … … … … … … … … … … … … … … ..[1 mark]

(b) Write the general formula of the homologous series that you are stated in (a).

CnH2n+2 , n=1,2,3 … … … … … … … … … … … … … … … … … … … … … … … … … ..[1 mark]

(c) Write the molecular formula of compound Y

C2H6 … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … ..[1 mark]

(d) What is observation when bromine water is added to ethene ?

Brown bromine water decolourises.… … … … … … … … … … … … … … … … … … … … … ..[1 mark]

(e) State the type of reaction when bromine water is reacted with ethene.

Addition reaction // bromintation … … … … … … … … … … … … … … … … … … … … .. [1 mark]

(f) (i) State the name of the products formed when ethene burnt completely in excess oxygen.

Carbon dioxide and water … … … … … … … … … … … … … … ...[1 mark]

(ii) Write the chemical equation for the reaction in (f) (i).

C2H4 + 3 O2 2 CO2 + 2 H2O … … … … … … … … … ...[2 marks]


10 Diagram show structural formula of four hydrocarbons.

A B C D

(a) Which two of structural formulae are isomer. Explain your answer.B and C. They have same molecular formula but different structural formula.

(b) Choose one hydrocarbon above, state the products formed when the hydrocarbon is burning and write the equation involved.A: Products: carbon dioxide and waterC4H8 + 6 O2 4 CO2 + 4 H2O

(c) Describe a chemical test how to differentiate hydrocarbon A and D.1 cm3 of liquid bromine is added into a test tubes containing A and D.A decolourise the brown bromine water. But D does not decolourise the bromine water

(d) Describe the preparation of ester ethylethanoate1. 2 cm3 of ethanoic acid is poured into a test tube.2. 4 cm3 of ethanol is added into ethanoic acid.3. By using dropper, few drops of concentrated sulphuric acid are added slowly into the mixture and shaken.4. the mixture is heated until boil.5. the content is poured into a beaker half filled with water.6. ethylethanoate is formed on the top of the water layer.


OXIDATIOAN & REDUCTION

5 Diagam 5 shows the set-up of apparatus to investigate the reaction between iron(II) sulphate solution and acified potassium dichromate(VI) solution through the transfer of electrons at a distance.

(a) What is the colour of iron(II) sulphate solution?

Pale green … … … … … … … … … … … … … … … … … … … … … … … ..[1 mark]

(b) (i) Write the half equation for the reaction occur at X.

Fe2+ Fe3+ + e-… … … … … … … … … … … … … … ...[1 mark]

(ii) State the change in oxidation number of iron.

+2 to +3 … … … … … … … … … … … … … … … … … … ...[1 mark]

(c) The incomplete half equation occur at Y is :

Cr2O72- + 14 H+ + 6e → 2 Cr3+ + 7 H2O

Complete the equation. [1 mark]

(d) On the diagram above, show the direction of electrons flow. [1 mark]

Diagram 5


(e) You are provided with the following :

(i) By using the given materials and apparatus, draw the set-up of apparatus to investigate the redox reaction through transfer of electron at a distance.

2 marks]

(ii) On your diagram in (e) (i), indicate the positive and negative terminal.[1 mark]

(iii) State the change in oxidation number for bromine in this reaction.

0 to -1 … … … … … … … … … … … … … … … … … … … ...[1 mark]

5. Diagram 5 shows the set-up of apparatus to investigate the reaction occurred in test tubes A and B.

Bromine water Potassium iodide solution Carbon electrodes Beaker Porous pot Connecting wire

Diagram 5


(a) Based on test tube A,

(i) Name the reaction occurred.Redox reaction ...............................................................................................

[1 mark] (ii) Write the ionic equation for the reaction.

Cl2 + 2 Fe2+ 2 Cl- + 2 Fe3+ .....................................................................[2 marks]

(iii) State a chemical test to verify the product formed.Add Potassium thiocyanate, KSCN solution, a blood red solution produced,

show the present of Fe3+ ions. [2 marks]

(b) Based on test tube B,

(i) State the observation involved. No dark blue precipitate formed.........................................................

[1 mark]

(ii) Experiment is repeated by using copper to replace zinc. State the observation involved.A lot of dark blue precipitate formed.

[1 mark]

(c) Compare the answer in (b)(i) and (b) (ii) and explain why there is a difference in the observation.

When two metals are in contact with each other, the more electropositive metal will loss electrons (undergoes oxidation) and become corroded, and the less electropositive metal will be protected from being corroded.

[2 marks]

(d) When iron is exposed to water and oxygen, it rusts easily. State one method to prevent the rusting of iron.

Alloying ..................................[1 mark]


THERMOCHEMISTRY10 (a) Diagrams 10.1 and 10.2 show two energy level diagrams.

Diagram 10.1 Diagram 10.2

(i) Compare both the energy level diagrams above. Your explanation should include the following : ionic equations type of chemical reactions energy content of reactants and products

Diagram 10.1 Diagram 10.2Ionic equation Mg + Fe2+Mg2+ + Fe Ca2+ + CO3

2- CaCO3

Chemical reaction Displacement of metal Precipitation reactionEnergy content Energy content of reactants is

higher than productsEnergy content of reactants is lower than products

[6 marks]

(ii) Based on Diagram 10.1, calculate the change in temperature of the solution if excess magnesium powder is added to 50 cm3 of 0.2 mol dm-3 iron(II) sulphate solution.[Specific heat capacity of solution : 4.2 J g -1 oC-1]Number of mol = 0.2(50)/1000 = 0.01 mol

H =001.0

Q

mol

Q => Q = 200000 x 0.011 = 2000 J

Q = mc => = 2000/50(4.2) = 9.5 oC[3 marks]

(b) Table 2.2 shows the heat released for Experiment I, II and III using different acid that has been reacted with sodium hydroxide solution.

Experiment Chemical Equation Heat released (kJ)I HCl + NaOH → NaCl + H2O 57

II CH3COOH + NaOH CH3COONa + H2O 54

III H2SO4 + 2NaOH Na2SO4 + 2H2O 114

Table 2.2Based on Table 3.2, explain the difference in heat released between :

Mg + FeSO4

MgSO4 + Fe

Energy Energy

CaCl2 + Na2CO3

CaCO3 + 2NaCl

ΔH= - 200 kJ ΔH= + 12.6 kJ


(i) Experiment I and Experiment II(ii) Experiment I and Experiment III

1. The heat of reaction in Experiment I is lower than that of Experiment III2. Hydrochloric acid is a monoprotic acid3. mol of hydrochloric acid ionises completely in water to produce 1 mol of hydrogen ion4. HCl → H+ + Cl-

5. Sulphuric acid is a diprotic acid6. mol of sulphuric acid ionises completely in water to produce 2 mol of hydrogen ions.7. H2SO4→ 2H+ + SO4

2-

8. Therefore, the heat of neutralisation of sulphuric acid is twice as much as the heat of neutralisation of hydrochloric acid

[6 marks](c) Describe a laboratory experiment to determine the heat of displacement of metal by a more

electropositive metal. In your description, include the following aspects: Materials and apparatus needed Procedure of experiment A table to collect data Calculation method [10 marks]

CONSUMER8 (a) Diagram 8.1 shows the structure of anion parts of a soap and a detergent. These anions consist of part

A and part B as shown in the diagram.

Part A Part B

Diagram 8.1

(i) Name part A and part B of the anions.State the solubility of part A and part B in the cleansing action.Part A: hydrophobic tail –soluble in greasePart B: hydrophilic head –soluble in water

[4 marks]

(ii) Compare the effectiveness of the cleansing action of the two anions shows in the diagram 8.1 in hard water. Explain your answer.Write an ionic equation to show the reaction of anion of soap in hard water.

Anion of a soap

Anion of a detergent


[6 marks]

(b) Diagram 8.2 shows the label of soft drink.

Diagram 8.2

Based on the ingredient used, classify the type of food additives that contained in this soft drink.Citric acid: antioxidantAspartame: flavoringOctyl butanoate: flavoringTartazine: flavoring

[4 marks]

(c) A patient is suffering from tuberculosis for a period of time. Suggest a type of medicine that should be taken and the prescription should be followed by the patient.1. Antibiotic –streptomycin.2. Patients should take full course of the antibiotic even if he feels better because:

3. To make sure that all the bacteria are killed. Otherwise he may become ill again and the bacteria become more resistant to the antibiotic. Stronger antibiotic is needed to fight the same infection. [4 marks]

Ingredient :

Water, citric acid, aspartame, octyl butanoate and tartazine.Expiry date : 03 Jan 2011

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Ulangkaji Akhir Menjelang Spm Answer