chem 8 P2 1st term 09.doc

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Madhrasathul Ahmadhiyya, MaleFIRST TERM TEST - 2009

CHEMISTRYPAPER-2Grade - 8

Duration: 1 hours

Name:............................................................... Grade: Index: Reg no: .

AnswerAll questions

1- The table below shows the melting point, the Boiling Point and density of substance A to D

Substance M.P/c B.P/c Density/gcm-1A 1110 2606 9.1

B -266 -252 0.07

C 40 94 1.6

D -14 60 0.9

[5]

(a) Which substance is a gas at room temperature? ....

(b Which substance is a liquid at room temperature? ...

(c) Which substance is a solid at room temperature? ..

(d) Which substance is most likely to be a metal? ...

(e) What is the melting point of the least dense non-metal? .

2- (i) How many atoms of the different elements are there in the following formulae of

the compounds given below?

[5]

(a) Nitric acid, HNO3 .

(b) Copper Nitrate Cu (NO3)2 ..

(ii) A student was given two beakers. One containing rain water, the other contained

sea water. The student placed a thermometer in each sample and heated it until

boil.

(a) Did the rain water boiled at lower, higher or the same temperature as the sea water?

Madhrasathul Ahmadhiyya First Term Test 2009 Chemistry Grade 8 Paper-2 Page 1 of 5


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(b) Sea water contain salts, which salt is present in the greatest percentage?

(c) Name the process by which sea water may be converted into drinkable water

3- (a) Explain the difference between ionic and covalent bonding [2]

Ionic Bonding Covalent Bonding

(b) Draw diagrams to show the bonding in each of the following covalent compounds [4]

(i) Tetra chloromethane, CCi4 (ii)Ethene, C2H4

(iii) Nitrogen, N2 (iv) Hydrogen Chloride, HCI

(c) Draw diagram to represent the bonding in each of the following ionic compounds: [4]

(i) Magnesium Fluoride MgF2

(ii)Calcium Oxide ( CaO)



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4- (a) Explain the terms [10]

(i) Malleable ...

(ii) Sublimation

(iii) Atomic Number ...

(iv) Valency

...

(b) Explain why metals are able to conduct heat and electricity.

(c) Draw diagrams to show how the electrons are arranged in[Na=11;Cl=17]

(i) Sodium Ion (ii) Chloride Ion

(d) Write the chemical formula of the following compounds

(i) Zinc chloride .

(ii) Aluminum Fluoride ....

(iii) Silver Oxide ..

5- The Diagram shows the arrangement of the outer electrons only in a molecule of ethanoic

acid.

[5]



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(a) Name the different elements found in this compound.

..

(b) What is the total number of atoms present in this compound?

(c) Between which two atoms in there a double covalent bond?

(d) How many single covalent bonds does each carbon atom have?

(e) Write two properties of the above compound you expect to have.

6- Fill in the blanks with the word given below :

Sublimation, Atomic Number, Metallic Bonding, Fractional Distillation, Freezing

[5]

(a) The modern periodic table is arranged in order of increasing .

(b) The best method for separating a mixture of ethanol (B.P 79c) and water (B.P 100c) .

...

(c) Changing of ammonium chloride directly into a gas by heating

...

..(d) An electrostatic force of attraction between the mobile sea of electrons and the positive metal

ions within the solid metal is called ...

(e) Changing a liquid into a solid ....

7- Use the Information given in the table below to answer the questions below concerning the

element Q, R, S, T and X

ELEMENT ATOMIC NUMBER MASS NUMBER ELECTRON

STRUCTURE

Q 3 7 2,1

R 20 40 2,8,8,2

S 18 40 2,8,8

T 8 18 2,6

X 19 39 2,8,8,1

[5]

(a) Which element has 22 neutrons in each atom?

...

(b) Which element is a noble gas?



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(c) Which two elements form ions with the same electron structure as neon?

(d) Which tow elements are in the same group of the periodic table and in which group in this?

.

(e) Which is the most reactive metal elements shown in the table?

8- (a) The first element in group 7 is fluorine. Would you expect it to be: [5]

(i) A gas, a liquid or a solid? ..

(ii) Coloured or colourless? ..

(iii) Harmful or Harmless?

..

(iv) More reactive or less reactive than chlorine? ...

..

(v) A monatomic or diatomic molecule? ...


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chem 8 P2 1st term 09.doc