SEKOLAH MENENGAH KEBANGSAAN SIMPANG RENGAMMID-YEAR EXAMINATION 2010CHEMISTRY PAPER 2 FORM FOURTWO HOURS AND THIRTY MINUTES

NAME ...............

……………………...........

FORM : 4…….

SECTION A[60 marks]

Answer all questions in this section.1. Graph 1 shows the temperature against time of solid substance X when heated. Substance X

is an organic compound and flammable.

a) (i) State the melting point of substance X

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

(ii) What is the state of matter of substance X at :

PQ : ...............................................................................................................................

RS : ...............................................................................................................................[ 2 marks]

(iii) Explain why the temperature remains constant from Q to R?

........................................................................................................................................

........................................................................................................................................[ 2 marks]

(iv) State how the movement of substance X particles changes between R and Sduring heating.

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

b) If substance X cooled to the room temperature, draw the graph oftemperature against time obtained.

[ 2 marks]

Section Question

Full mark mark

A1 102 103 104 105 116 9

B 7 20C 8 20

Total

Graph 1

c) Draw the arrangement of particles for substance X at 90oC

[ 2 marks]

2. Table 2 shows the number of proton, electrons and neutrons for atom P, Q and R

Atom Proton Number Nucleon NumberP 11Q 17 35R 17 37

Table 2(a) What is meant by nucleon number?

......................................................................................................................................................

......................................................................................................................................................

[ 1 mark](b) State the nucleon number of P if the number of neutron is

12 .....................................................................................................................................................

[ 1 mark]

(c) Write the symbol of atom P in the form of Y

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

(d) Write the electron arrangement of atom Q

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

(ii) What is the number of valance electrons in atom Q.

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

(e) Which atoms are isotopes? Explain why.

......................................................................................................................................................[ 2 marks]

(f) Table 3 shows four substances and their respective formulae.Substances Chemical formulaIodine  I2

Copper  CuNaphthalene  C10H8

Copper (II) Sulphate  CuSO4

Use information from table 3 to answer the following questions.(i) State one substance which exist as a molecule.

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

(ii) Which substance can conduct electricity in the solid or molten state?

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

(iii) What type of particle presents in copper(II) sulphate?

A

Z

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

3. Table 4 shows formula of four ions.Name of ions Sodium ion Magnesium ion Sulphate ion chloride ionFormula of ions  Na+ Mg2+  SO4

2-  Cl- 

(a) Write the formulae for each compound below :

(i) Sodium sulphate : ................................................................................................................

(ii) Magnesium chloride : .......................................................................................................

(iii) Sodium chloride : ...........................................................................................................

(iv) Magnesium sulphate : .........................................................................................................

[4 marks](b) When Sodium metal is added to water, metal hydroxide solution and hydrogen gas are formed.(i) Identify the reactants and products of the reaction.

Reactants : ................................................................................................................

Products : ..................................................................................................................[2 marks]

(ii) Write the chemical equation for the reaction occurs in (b).

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

(c) The following equation shows the decomposition of hydrogen peroxide,H2O2

2H2O2(l) 2H2O(l) + O2(g) Calculate the volume of oxygen gas, O2 measured at STP that can be obtained from the decomposition of 34 g of hydrogen peroxide,H2O2

[Relative atomic mass, O= 16, H=1, molar volume of gas at STP 22.4 dm3 ]

[3 marks]

4. In an experiment to determine empirical formula for substance R, The percentages composition by mass for each of element has been obtained as follows;

[Relative atomic mass, Mg=24, S=32, O=16, C=12]a) What is meant by empirical formula ?

……………………………………………………………………………………………………………

………………………………………………...................................................................................

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

b) Based on the result of the experiment, determine the empirical formula for R.

[3 marks]c) Draw set up apparatus to determine the empirical formula of Magnesium Oxide in laboratory

[2 marks]d) Substance L, has the empirical formula CH2O.

i) If the relative molecular mass for L is 120, determine the molecular formula for this substance.

[2 marks]ii) Calculate the percentage by mass of carbon element in the substance L.

[2 marks]

Mg = 20.0% S = 26.7% O= 53.3%

5. Diagram 5 shows part of the periodic table of elements P, Q, R, S, T, U and V do not represent the actual symbol of the elements.

Using the letters in the periodic table of elements in diagram 2, answer the following questions.

a) How is the elements arranged in periodic table

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

b) Write the electron arrangement of atom T

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

c) Arrange the element P, Q,R, and T according to the atomic size in ascending order.

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

d) Which Element exists as a monoatomic gas. Explain why.

………………………………………………………………………………..........................................

………………………………………………………………………………..........................................[2 marks]

e) Q and T have same chemical propertiesi) Which element is more reactive

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

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

[1 mark]

f) State the position of element S in the periodic table

………………………………………………………………………………..........................................[2 marks]

g) Which element is the transition element. State one special characteristic of transition element

………………………………………………………………………………..........................................[2 marks]

6. Period 3 consists of the elements as shown below

P

Q R S

T U

V

Na, Mg, Al, Si, P,S,Cl,Ar

a) Pick an element that conducts electricity.

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

b) How does the atomic radius change as we go across the Period from left to right. Explain your answer

………………………………………………………………………………………………………………….[2 marks]

c) Pick an element that exists as a monoatomic.………………………………………………………………………………………………………………….

[1 mark]

d) Which element formed amphoteric oxide when react with oxygen.Write the formula of the oxide form

………………………………………………………………………………………………………………….[2 marks]

e) Pick an oxide which is basic and can dissolve in water.………………………………………………………………………………………………………………….

[1 mark]

f) Write an equation for the reaction when this oxide dissolves in water.

………………………………………………………………………………………………………………….[2 marks]

SECTION B[20marks]

Answer the question from this section.

7) Figure shows the standard representation for four element, Carbon, Oxygen, Sodium and Chlorine.

a) Construct a table to compare the four elements, with respect to the following

The number of protons. The number of neutrons The electron arrangements The number of valence electrons.

[8 marks]b) Element M has 19 of proton number. State the Group and The Period of element M in

Periodic Table. Explain your answer

[4 marks]

c) Compare the matter in solid, liquid and gas formed in terms of ;i) Arrangement of particles.

C O Na Cl12

6

16

8

23

11

35

17

ii) The movement of particles.iii) The force of attraction between particles.iv) The energy content.

[8 marks]

SECTION C [20 marks]

Answer the question from this section.

8) Empirical formula for magnesium oxide can be determine by combustion magnesium metal with excess oxygen gas.

(i) Describe the experiment conducted to determine the empirical formula of magnesium oxide. Your experiment should include

Diagram of set up apparatus. Procedure. Tabulation of data Calculation Precaution.

[15 marks]

(ii) Write the balance chemical equation for the reaction between magnesium metal with oxygen gas to produce white magnesium oxide

[2 marks]

(iii)Calculate The mass of magnesium oxide produce if 0.1 mol of oxygen gas is use in this experiment.

[3 marks]

Prepared by, Certified by,

……………………….. …………………………

(Sensrazazli B Baharim) (Pn Chua Hwee Kian)

Marking Scheme Form 4 Chemistry Paper 2Section A

1. a)i) 800C 1m

ii)PQ : Solid RS : Liquid 2m

iii) Energy is absorbed by particle to overcome the force of attraction between particle. 2miv) Move faster. 1m

b) Room temperature, oC

-label axis with unit-1

- smooth curve -1

2m

Time,s

TOTAL 10M

c) .

2m

2. a) The total number of proton and neutron in a nucleus of an atom. 1mb) 23 1mc) P 1md) i) 2.8.7 1m

ii) 7 1m

e) Q and R, 1m

Have the same proton number but different nucleon number //Have the same number of protons but different number of neutrons.. 1m

f) I) Iodine / naphthalene 1mii) Copper / Copper(II) sulphate. 1miii) Ion. 1m

TOTAL 103. a) (i) NaNO3 1m

(ii) MgCl2 1m(iii) NaCl 1m(iv) Mg(NO3)2 1m

b) i) Reactant : Sodium and Water// Na and H2O 1m Product : Sodium hydroxide and hydrogen gas // NaOH and H2 1m

ii) 2Na + 2H2O 2NaOH + H2 1m

c) Mol of H2O2 = 34/34 = 1 mol 1m

Mol of O2 = ½ X 1 = 0.5 mol 1m

Volume of O2 = 0.5 x 22.4 = 11.2 dm3 1m

TOTAL 10M

4. a) Empirical formula is formula that show simplest whole number ratio of each atom in the

compound. 1M

b) .

1M

1M

1M

c) .

Functional diagram – 1

Labeled – 1

2M

d) (CH2O)n = 120

12 n+ 2n + 16n = 120

30n = 120

n = 4 1m

molecular formula = C4H8O4 1m

e) Mass of carbon in substance L = 2 X 12 = 24 1m% of carbon in substance L = 48/ 120 X120 = 40% 1m

TOTAL 10m5. a) in order of increasing proton number. 1m

b) 2.8 .1 1mc) P, R, Q, and T 1md) P 1m Because atom P Atom P has stable / duplet electron arrangement 1me) i) T 1m

ii) Larger size easy to release electron/ more electropositive. 1mf) Group 17 1m

Period 2 1mg) V, 1m

Show different oxidation number. Form coloured compound. Use as catalyst. 1m[any one]

TOTAL 116. a) Na /Mg /Al 1m

b) Decrease, 1m Because the force of attraction between nucleus and electron is stronger. 1mc) Ar 1md) Al 1m Al2O3 1me) Oxide of Na / Mg 1mf) Na2O + H2O 2 NaOH // MgO + H2O Mg(OH)2 1m

TOTAL 9m

SECTION B

  Mg S O

mol20 26.7 53.324 32 16

ratio of mol

0.83 0.83 3.330.83 0.83 0.83

1 1 4Empirical formula

MgSO4

7. a)

[2 mark given to any correct row or column] 8m

b) – Atom M has 19 electron. 1m- Electron arrangement of atom M is 2.8.8.1 1m- Atom M located at Group 1 because has 1 valence electron. 1m- Atom M located at period 4 because has 4 shell filled by electron 1m

4mc)

Solid liquid GasArrangement of particle

The particles are packed closely together in orderly manner

The particles are packed closely together but not in orderly manner

The particles are very far apart from each other.

The movement of particle

Vibrate and rotate on their fixed position

The particles move freely, they collide against each other.

The particle move freely, the rate of collision is greater than the rate of collision in a liquid.

The force of attraction between particles

Very strong Less strong Weak

The energy content low medium higher[2 marks given to any correct row or column]

TOTAL 20m

8. (i)

1m

Procedure:

1. Clean magnesium ribbon with sand paper 1m

2. Weigh crucible and its lid 1m

3. Put magnesium ribbon into the crucible and weigh the crucible with its lid 1m

4. Heat strongly the crucible without its lid 1m

5. Cover the crucible when the magnesium starts to burn and lift/raise the lid a little at intervals 1m

6. Remove the lid when the magnesium burnt completely 1m

7. Heat strongly the crucible for a few minutes 1m

8. Cool and weigh the crucible with its lid and the content 1m

9. Record all the mass 1m

Tabulation of data

C O Na ClNo. of protons 6 8 11 17No. of neutrons 6 8 12 18Electron arrangement

2.4 2.6 2.8.1 2.8.7

No. of valence electron

4 6 1 7

Mass/gCrucible + lid xCrucible + lid + magnesium yCrucible + lid + magnesium oxide

z

1mCalculation :

2mEmpirical formula: MgaOb / MgO 1m

PrecautionRepeat the processes of heating, cooling and weighing until a constant mass is obtained 1m

ii ) 2 Mg + O2 2MgO 2m

iii) Mol of MgO = 2 X 0.1 = 0.2 mol. 1mMass of MgO = 0.2 X 40 1m

= 8 g 1m

TOTAL 20M

END OF MARKING SCHEME

Element Mg OMass (g) y-x z-y

Number of moles

Simplest ratio of moles a b